12mm test tubes (5mL, 12 x 75mm) for use in the 12mm Test Tube Holder for the RF5301. Package of 72. Made of Pyrex and useable to 350nm. (For actual test tube holder see part # 206-67777-00). Can also be used with FRC-40/LH-40 Rack Kit D12, Part # 228-75604-43.