FSA 45

FSA 45
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 90.
Rated 1 out of 5 by from Wimpy trimmer Battery life sucksBlades suckToo wimpy for even small jobs
Date published: 2019-08-12
Rated 5 out of 5 by from Great battery life Light weight and great power to cut down tall grass and 1/4" brush.
Date published: 2019-08-09
Rated 5 out of 5 by from Works great I bought this because it is battery operated. Reviews said the battery doesn't last, however I have not had an issue. I am amazed with the power it has. Just right for someone to trim around flower beds.
Date published: 2019-07-29
Rated 1 out of 5 by from Polycut blades suck The trimmer itself is not a bad product. However, the polycot blades that are sold with the unit are worthless. I need to replace the blades after every use (normal non-commercial usage on a small yard). The "suggestion" to soak the blades before use is not on any of the packaging. The soaking doesn't help much anyway, but I am unhappy at being asked to perform this extra step. I have not had to do this on other brands of trimmers that I have owned, and would not have purchased this trimmer had I known about the requirement to soak the blades ahead of time.
Date published: 2019-07-15
Rated 5 out of 5 by from Good Product I bought this for my bank that i planted flowers on. It lasts around twenty to thirty minutes. To be able to tilt the head on it helps ALOT. I am 64 and it is easy on the back!! Highly recommend this product and very grateful that this is manufactured!!!
Date published: 2019-07-10
Rated 5 out of 5 by from Great features, lightweight and no line to deal with! The two blades cutting wheel alone sold me on the Stihl. I love mine! It's flexible and and powerful, get the job done!
Date published: 2019-07-09
Rated 1 out of 5 by from The replacement blades do not last Trimming is done along sidewalk and brick planters. The plastic blades wear down to an unuseable length very quickly. The product should have come with100 replaceable blades to be satisfactory. Shouldn’t have bought this product
Date published: 2019-07-08
Rated 5 out of 5 by from Does the Job So far we love this trimmer. It's very easy to use, powerful enough for a small yard and charges quickly. I've changed the orange plastic "blades" once and it was easy. I'm really surprised at some of the thickness this trimmer handles. Perfect for us seniors.
Date published: 2019-07-06
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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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