A spread of sizes across a clip type in one box. Worm drive assorted in 2, 5 or 10 of each size (36, 90 or 180 clips); T-bolt assorted (46, 100 or 210 clamps); mini fuel clips (22, 55 or 110); and rubber-lined P-clips (20, 50 or 100). Available in W1 zinc and W4 stainless.

Because you rarely know in advance which size the next job needs. An assorted box means the right clip is on the shelf rather than being a trip to the merchant halfway through a repair. For a workshop, farm or van, that is worth considerably more than the price difference.

Per clip, yes - substantially cheaper than buying the same clips as singles. The larger boxes are better value again. The only case where singles make more sense is when you know exactly which size you need and will never need the others.

Worm drive for general coolant, water and air work - the box most people want first. T-bolt if you build or repair charge air systems. Mini fuel clips for small-bore fuel, oil and vacuum lines. P-clips for mounting and supporting runs. Many workshops end up with all four.

W4 stainless for anything exposed to weather, coolant, road salt or damp - which covers most engine bay, outdoor and agricultural work. W1 zinc plated is cheaper and fine for dry indoor use. In a bulk box the price difference is small compared with the cost of a seized clip.

Worm drive spans 18 ranges from 9mm to 12mm up to 135mm to 165mm. T-bolt spans 23 ranges from 17mm to 19mm up to 122mm to 130mm. Mini clips span 11 ranges from 7mm to 9mm up to 18mm to 20mm. P-clips cover 10 sizes from 5mm to 35mm.