(Click to see larger image) Never worry about knocking over a rack of test tubes again! Our Super Polyester Test Tube Racks hold and lock your tubes securely and have a low profile which makes them virtually impossible to tip over. Not only are they lightweight - less than 2 ounces - but they float on water, even when full of samples. In addition, they are flame-retardant and chemical and solvent resistant. These racks for securely hold 50 5-10 mL culture tubes or 15mL conical tubes. Each stretchy hole is approximately 13mm in diameter. Each rack is approximately 22cm x 13cm x 4.3cnm and the hole pattern is 5 x 10.