Anti-slip inserts (sometimes called grips or anti-slide inserts) are inserts made of a grippy material that help prevent the foot from sliding around or slipping out of your shoe when wearing footwear. The most common usage for anti-slip inserts is to prevent heel slippage when wearing shoes by placing anti-slip pads around the back of the shoe near the ankle. The pads help to prevent the heel from lifting upwards out of the shoe when walking. Anti-slip inserts come in many shapes and sizes and can be used wherever needed inside your shoes.