This device hooks over the edge of a worktop & the jar or bottle is then placed in the V. The object is clamped by the ram, which can be pushed with the stomach or hip, leaving hands free to twist the top. The device is made from moulded plastic with non-slip feet & rubber lining. Can be used with most jar or bottle openers. Suitable for items up to 120mm (43/4") diameter. Measures 330 x 190 x 90mm. Weight 580g.