This is a replacement line trimmer bump cap found on several models of trimmers. This bump cap is used to hold the spool and bumper in the spool housing. It provides some protection to the line spool. If this piece is damaged or broken, it will not keep the line spool safe and in place.The bump cap is made from durable plastic. However, it still can break or start to wear down. Parts of it could crack and chip. Check the bump cap occasionally and replace it if it is showing signs of damage. The replacement is easy. The old cap can be removed by pressing on the two tabs, and then a new one can be added. The replacement should take a matter of minutes.This bump cap is compatible with certain models of trimmers from Black & Decker and DeWalt. The cap is sold individually. It is a genuine OEM replacement product.