Be sure to place LS-0425 Tube Clamp Sleeve with LB-0425-01/M3/M5/M6 and LS-0640 Tube Clamp Sleeve with LC-0640 Barb Straights on edge of outer tube in order to avoid the escape of tubes.

Please note difference in 1/4" sizes
1/4" x 0.163" Polyurethane Tube
1/4" x 0.180" Nylon Tube