Use a CoolBox XT 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 XT ice-free cooling workstation.  

Place in between the the base of the CoolBox XT 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: 14.0 x 9.4 x 7.0 cm / 5.5 x 3.7 x 2.8 in
External: 20.0 x 16.0 x 7.0 cm / 7.9 x 6.3 x 2.8 in

CoolBox XT Extension Collar is available in 4 colors
BCS-502-C, purple
BCS-502CG, green
BCS-502-CO, orange
BCS-502-CPK, pink