If you own a Black+Decker string trimmer, you'll eventually need replacement line. The AF-100 0.065" spool is one of the most common replacements for their equipment, but with dozens of trimmer models in the Black+Decker range, it's worth understanding which ones actually use it and how to maintain your cutting line properly.

Understanding the AF-100 and Compatibility

The AF-100 is a replacement spool system designed to work with a wide range of Black+Decker trimmer models. The model number AF-100 itself refers to the spool design, while the 0.065" measurement indicates the thickness of the trimmer string that goes on it. This thickness is important because not all Black+Decker trimmers accept the same string diameter.

Black+Decker trimmers that accept AF-100 spools include models from several series: the GH series (GH400, GH500, GH600, GH610, GH900, GH912), the ST series (ST6600, ST7000, ST7200, ST7700, ST7701, ST8600, ST9000), the CST series (CST1000, CST1100, CST1200, CST2000), as well as MTC220, MTE912 and NST models. The LST series also uses this spool, as do BESTA and BESTE models. Before purchasing, check your trimmer's manual or look for the model number printed on the machine itself—usually on a sticker near the motor or handle.

Identifying Your Exact Trimmer Model

Finding your model number is straightforward. Look for a label on your Black+Decker trimmer that lists the model designation. It will typically be printed near the base of the motor, on the battery compartment, or along the shaft. Write down the full model number and cross-reference it with the compatibility list to confirm it uses the AF-100 spool. If you've lost your manual, the model number is your most reliable tool for matching the correct replacement.

It's also worth noting that some Black+Decker trimmers have variant model numbers, indicated by suffixes like -3ZP, -BKP, or -2. These variants may use the same AF-100 spool despite the slightly different model designation, so don't assume a different suffix means you need a different spool.

String Thickness and Cutting Performance

The 0.065" specification refers to the diameter of the nylon line. Thicker string generally lasts longer and handles tougher vegetation, while thinner string is lighter and better for delicate trimming around flower beds. At 0.065", this is a medium thickness suitable for general lawn maintenance. The string is made from nylon polyamide, which is pliable enough to flex on impact with hard surfaces like rocks and concrete, reducing breakage and improving overall efficiency compared to rigid alternatives.

How Often to Replace Your Spools

How quickly you deplete a spool depends on how much trimming you do and what vegetation you're cutting through. Dense, tough weeds consume string faster than light grass. A typical spool of 240 feet will last most homeowners several weeks of regular use during growing season. If you trim weekly during summer, having extra spools on hand prevents downtime. A 10-pack gives you a full year's supply for typical residential use.

Maintenance and Storage

Store unused replacement spools in a cool, dry place away from direct sunlight, as ultraviolet exposure can degrade nylon over time. When installing a new spool, wind the string evenly and ensure it's seated properly in the AF-100 spool head. Most Black+Decker spools with AF-100 designation use automatic feed systems, meaning the centrifugal force from the trimmer head releases new line as the existing line wears down. This means less manual adjustment during use, though you'll still need to replace the entire spool once it's fully depleted.

Keep the spool head and feed mechanism clean by brushing away grass clippings and debris after each use. This helps the AF-100 spool feed smoothly and prevents jamming.

The product in this guide: 10 Pack Weed Eater String Compatible with Black+Decker, AF-100 0.065" 240ft