25mm Polytunnel Cover Clamps. Polytunnel Cover "Grip-Clips" - Pack of 20. Suitable for 25mm Diameter Polytunnel Frames. "Polytunnel Grip-Clips" clamp polytunnel covers to front & rear hoops to form a "Goliath-Grip"; cover to frame, forming a strong attachment in adverse weather conditions.    Suitable For:  Polytunnels  Greenhouses Comes complete with a 30 day manufacturers warranty against manufacturers defects; and a further 6months warranty against component failure - storm damage not included.