The Black & Decker MTD100 3-in-1 Removable Mower Deck is actually 3 tools in 1, which can easily convert a 12 trimmer/edger to a mower. It has an adjustable height deck (2 settings) for ideal cutting height. Compatible with: NST2118, LST220, LST300, LST400, LST522, LSTE522, LSTE523, LSTE525. It also features a wall hanging option to make storage much easier when not in use. This mower deck is ideal for smaller sized yards (ideal for properties up to 700 sq. feet) and also great for inclines or areas difficult to mow with standard mowers. Unit includes: (1) MTD100 detachable mower deck. (String trimmer not included).