Use a CoolBox 2XT Extension Collar when keeping tall tubes such as 3, 4, or 5 mL cryovials, 15 mL or 50 mL centrifuge tubes and blood collection tubes in the CoolBox 2XT ice-free cooling workstation.  

Place in between the the base of the CoolBox 2XT system and the original collar.  Magnets on top and bottom provide a secure connection to the base and original collar. 

Dimensions (L x W x H):

Internal: 21.0 x 14.3 x 13.4 cm
External: 26.5 x 20.0 x 15.0 cm