Swivel symmetrical clip for double-sided grinding without reinstalling of knife. Clamp structure allows to clamp symmetricaly and rigidly knives with complex blade geometry. It has an independent mechanism of reinstall clamping sponges. It's suitable for cutlery and fillet knives with narrow spine. In contrast to single clamp, thin knives can be pinched in double clamp only. Thanks to two clamp points thing knives are pinched more rigidly and they are not bent being in double clamp. But in contrast to single clamp double clamp has more narrow sponge of 16 mm in width therefore knives with spine more that 3.5 mm in width are not recommended to be pinched. Minimal distance between the sponges is 40mm., maximal 130 mm. Recommended knife length for the clamp is 30-300 mm. Minimal knife width 20mm, thickness in spine 3.5 mm, range of angles 10-32 degrees (range can be changed for wide knives). Clamp sponges are made from aglow sprung-spring steel 65 g.Suitable for K-01 model. Sponges, screws and flat springs can be bought separately.