Single bubble; Scratch free High optical clarity material Precision machined internal radius Black lines, internally fitted gives minimal errors These level vials are Perfect for adding to all stationary equipment that can be leveled, such as stoves, refrigerators, washing machines, milling equipment, refrigeration equipment, heat pumps, furnaces, air handlers, campers and any tool, device or object where level is important. Add one to many of your hand tools to know when you are working at level. These level vials are more than most level vials built into hand tools, they are made thicker and stronger. new and high quality ! No glue or adhesive is included Size: 10*10*29mm Material: Acrylic Color: green Weight: 28g(10 pcs) Package included: 4 x Square Bubble Level Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.