The DiversiTech 17616 is a 1/4 in. thick square washer for strut and accommodates up to a 3/8 in. bolt. It is designed to be used with 1-5/8 in. strut channels. Strut washers are used to join strut channels together or connect strut channels to other hardware. DiversiTech's strut accessory product line contains a broad range of nuts, clamps, hangers and more for a multitude of customized metal framing and hanging applications.