This GRS 520 Attachment Set Includes 8 small pins, 4 flat square pins, 2 rectangular inset-curve pins, 4 thick round inset pins, 8 rubber coated pins, and 2 leather-faced ring clamp pins in molded base. With a variety of pins that fit the upper jaw plates of every GRS Block, you can now instantly solve workholding problems and start working sooner. It weighs Approximately 0.9000 lbs. (0.4082 kg)