Fine-tooth ratcheting mechanism allows bands to be contracted in small increments Set contains fine-tooth ratcheting pliers and nine different size bands Used to compress and install piston rings Compression band sizes: 2-1/8"-2-3/8" 2-3/8"-2-5/8" 2-5/8"-2-7/8" 2-7/8"-3-1/8" 3-1/8"-3-3/8" 3-5/8"-3-7/8" 3-7/8"-4-1/8" 4-1/8"-4-3/8". TOOL PISTON RING COMPRESSOR SET 9 PC