The Solid Brass Mouse Restrainer is designed to comfortably restrain a mouse for tail vein injections or sampling. Specifications: Size: 2" x 4", Weight: 2 lbs. Able to warm for animal comfort and asodilatation of the tail. Solid brass maintains heat for extended periods. Weight provides a stable and secure placement on lab bench. Can be sterilized via autoclave, ETO, liquid, VHP. Long lasting.