FSA 45

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An affordable string trimmer including a built-in battery and adjustable shaft length.

Product Description

Part of the AI Series, the FSA 45 delivers STIHL quality at a value price. It features an adjustable shaft length to fit different user heights and enhance comfort. With its adjustable trimmer head, this tool can adapt to various trimming tasks. It comes standard with the STIHL PolyCut™ 2-2 mowing head, making it ideal to cut in hard-to-reach places and large areas of tall grass. Plus, you can trim the length of three football fields when its integrated battery is fully charged – that’s up to 1,080 feet. This STIHL AI Series trimmer is also just 5.1 lbs. (including battery) for easy portability and maneuverability. This trimmer is a great choice for occasional use on small properties.

Usage claim tested and verified by an independent third-party test laboratory. Run time may vary based on battery type, charge level and capacity, model, operating style and conditions. Comes with integrated battery and charger. 

View Our Usage Chart

Model Features

  • Reduced-Emission Engine Technology - Caring for Nature
    The STIHL Inc. “Caring for Nature” seal identifies its powered products that are more environmentally conscious, producing zero or low exhaust emissions. STIHL Inc. defines “low exhaust emissions” as being cleaner than EPA and/or CARB exhaust emission standards.

    More information

  • Hanging Loop
    Hang your cordless trimmer securely on a wall to save space using the loop in the handle housing.

    See it in action!
  • Activation Key
    When removed, the activation key helps prevent accidental use/startup of the product. Battery will still charge with activation key removed – charge lights also work as well
  • Rubberized Soft Touch Handle 
    Soft rubber texture is both easy to grip and makes the product comfortable to hold for extended periods. 
  • Battery Indicator Lights 
    This product is equipped with built-in indicator lights, showing the battery status and remaining level of charge.
  • Loop Handle
    A thumb screw allows the ergonomic loop handle to be easily adjusted to desired position without tools.  
  • Compact, ergonomic design
    The compact, ergonomic design provides more comfortable use.
  • Lightweight Portability
    Great for maneuverability and extended use.


23 cm (9")
WEIGHT (w/ Integrated Battery)*
2.3 kg (5.1 lbs.)
AI Series
RUN TIME (w/ Integrated Battery)
W/ STIHL PolyCut™ blade: Up to 20 min.
W/ Round Quiet Line .065": Up to 12 min.
*Weight without cutting attachment or guard. Comes with integrated battery and charger.

Important Information

WARNING! Improper use of any trimmer/brushcutter can cause serious or fatal injury. Read, understand and follow all safety instructions in your instruction manual. To reduce the risk of injury from blade contact, circular saw blades may be used on FS brushcutters that have a limitstop, a bicycle handle and double shoulder harness and not on FS brushcutters with a "J" handle or loop handle. Other rigid blades may be used on FS brushcutters having a bicycle handle, a "J" handle or a loop handle equipped with a barrier bar. To reduce the risk of eye injury always wear proper eye protection. Always use the appropriate deflector for the type of cutting attachment, as explained in your instruction manual.

Note: STIHL engine products with the Caring for Nature logo are cleaner than EPA Standards for exhaust emissions.

WARNING! Improper use of any power tool may cause serious or fatal injury. Read, understand and follow carefully the operating and safety instructions in your instruction manual before using such products.

STIHL products sold through U.S. STIHL Dealers are for distribution in the United States only.


FSA 45 is rated 3.2 out of 5 by 97.
Rated 5 out of 5 by from Great Value in a small package . I do trimming once a week around my house and occasionally at my other property . Has always worked flawlessly . It can normally handle all the light to medium trimming I have to do . Stihl has made a fantastic electric product .
Date published: 2019-09-20
Rated 2 out of 5 by from also disappointed I was told Stihl was the best. Reading other reviews, I'm sure they are great products. But I agree that the battery life should be longer, but it's the trade-off with the lightweight feature. BUT what really disappointed me, was the way the blades were gone in no time. I bought extra at the time (came with 6, bought 6 more) and I was not able to finish weeding along a 40 foot wall before I had gone through all 12! AND THEY CAN'T BE FOUND ON THE INTERNET!! I can't believe that even on the Stihl site, you can't buy blades for one of their products. Will see if I can return it to the store where I bought it, but I don't like having my time wasted. I was depending on this tool.
Date published: 2019-09-18
Rated 1 out of 5 by from Need more Power Grossly under powered. I thought i would try the electric machine, so i won't have to always have the gas, oil, loud motor, etc...etc....etc....and try it on my home yard, just a weekly residential light duty use. This machine wouldn't even make it around my yard without the battery going dead. It won't cut around landscape borders, mailbox posts, trees, etc....etc....etc....all it will do is ruin the plastic blades (in lieu of the string) Good idea, but doesn't deliver even for light duty residential use. Going back to "upgrade" to the real Stihl machines that have performed well in the past. My ratings are based on the short lived battery, hence can't depend on it finishing the job due to its under power, and therefore, if it can't get the job done, it can't be a good value at any price.
Date published: 2019-09-16
Rated 5 out of 5 by from Easy to handle The unit is lightweight and easy to handle. The battery has a long run time for simple trimming and the blades are easy to change.
Date published: 2019-09-16
Rated 5 out of 5 by from Easy to use I wanted a trimmer that would be easy for me to handle, to start, and to change out the blades. This trimmer plugs in to a charger just like your phone. The plastic blades are super easy to change out. No messing, no fuss. I love it!
Date published: 2019-09-09
Rated 1 out of 5 by from No battery life You're lucky to get 10-15 min. Use from this product without charging. The blades broke right away, so it defeats our purpose in buying this model to have to use stringline. Unit is lightweight, but so is its trimming power. Wish we had returned it the 1st week!
Date published: 2019-08-27
Rated 2 out of 5 by from Pro: Battery Operated and Light weight Cons: battery life sucks, no way I could trim the length of 3 football fields. Blades don't last. FIRST TIME STIHL purchase***I bought this product because I always heard STIHL was a great product, and because I've tried several brands that just don't hold up. I use my trimmer to trim around my house, fence, and mailbox, but the battery doesn't last more than 30 minutes, and the blades have to be changed 2 to 3 times every time! Yes, they are easy to change, but they just don't last even through 1 use. Your website says you can trim the length of 3 football fields (1080 feet), but there is NO WAY you can do this with this battery. I didn't see on the website that the run time is only 9 minutes...if I had seen this, I would NOT have purchased this product!!! At this point, I'm very disappointed and frustrated this product is no better than the others I've had. I'm taking it back to ACE Hardware where I bought it, and look for something else. I would NOT recommend this product.
Date published: 2019-08-22
Rated 1 out of 5 by from Wimpy trimmer Battery life sucksBlades suckToo wimpy for even small jobs
Date published: 2019-08-12
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Product Instruction Manual (PDF)
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Cutting Heads & Blades Selection Chart (PDF)
Download Instructions on How to Rewind Your Trimmer Head (PDF)
Product Safety Manual (PDF)
STIHL Limited Warranty
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