Step-less clamps are designed to tighten in an exact circle around the hosing, simply use a crimping tool or the middle cutter on your pliers to crimp (not squeeze) the step-less clamp closed.
For use with 1/4" ID x 3/8" OD PVC Hose
These 7-10mm clamps will also work with the 4mm ID EVABarrier lines on a 1/4" barb. Due to the thicker internal wall the smaller 6-8mm clamps will not fit.