This one of a kind tool is used to clean the lug recess area on the AR-15 and AR-10 rifles. The lug recess area collects a lot of grease and debris and needs to be cleaned regularly. This tool compresses a cotton roll and then releases it so you can rotate it inside the lug recess area. Should be used wet with solvent, then followed up with a dry roll. One bag of cotton rolls, about 50, is included with each tool.