The smallest clamp in this range, covering an 8mm to 12mm hose outside diameter. It is the one you need for vacuum and boost reference lines, small breather and washer hoses, and low-pressure fuel connections on fine plumbing. At this size the clamp must be seated properly over the barb and tightened gently, as small soft hose is easy to cut through with an over-enthusiastic screwdriver. Position the band so the tail cannot chafe against a loom or adjacent line. Check the hose outside diameter before ordering, since a clamp at the very limit of its range will not develop even pressure around the joint.