A quick turn of the twist-lock sanding disc locks it securely into the backing pad.
The HERCULES™ 3 in. Type TR/III Twist-Lock Backing Pad is ideal for fast, precise general purpose sanding and finishing. This medium density backing pad works with most 3 in. twist-lock sanding discs. Includes a pad adapter to convert the 1/4 in.-20 female thread to a 1/4 in. diameter shank for use with collets and chucks