Features Premium Materials The locking head is made of high quality metal material, strong and sturdy, and not easy to break or damage. Cap Handling This capping head works with an electric cap sealing machine, can easily tight, loosen or twist different nut caps, saving strength and improving efficiency. For 20mm to 30mm: the locking head is specially designed for fasteners with a diameter of 20 30 mm, very functional and practical. Easy to Use This capping head is easy to install and operate and suitable for most high strength bottle caps. Precise Size The capping head is precision processed, with accurate shank size, can perfectly connect with the machine. Specification: Item type: head of electrical sealing machine. Material: metal, rubber. Cover diameter: approx. 20-30 mm/0.8-1.2 inches. Bottle height: Unlimited Rubber pad outer diameter: approx. 40 mm / 1.6 inches. Rubber pad height: approx. 17 mm / 0.7 inches. Package list: 1 x electric lock machine head. Note: Use immediately after confirming the size. Package List 1 x Electric Cap Sealing Machine Head