Connection clip: To attach a tarpaulin to the hoops with an external diameter of 11 mm. of a greenhouse. Please check the diameter of the poles before purchasing. Sturdy material: These greenhouse clamps are made of high quality ABS plastic which is strong, cold-resistant and has a long service life. Greenhouse Clamps: Convex surface design, won't slip from your fingers when clamped, firm shiny surface, to fix the greenhouse tarps well and play an effective protection role. Fixing function: Allows quick and easy attachment of waterproof fabric, shade fabric or netting to any type of tubing. Wide Applications: These greenhouse clamps are used to secure tarps, sun shades, greenhouse films or nets on tubes, and are also ideal for the construction of greenhouses, ground protection, etc.