Snap-on Flank Drive Plus Ratcheting Wrenches: Filling Out the Set From 10 mm Down to 5.5 mm

Introduction

Some tools earn their place through necessity, and some earn it by slowly gnawing away at you until you give in. This is a story of both. The Snap-on 10-piece metric Flank Drive Plus reversible ratcheting combination wrench set covers 10 mm through 19 mm with no skips, and it has become a favorite shop set for good reason. But once you own a set like this, filling in the gaps below 10 mm becomes almost impossible to resist, which is exactly how a tiny 5.5 mm wrench ends up in the roll.

Snap-on 10-Piece Flank Drive Plus Reversible Ratcheting Wrench Set (10-19 mm)

This set runs a complete metric range from 10 mm to 19 mm with no skipped sizes, which is what you want for shop use. Skipping sizes makes sense for a minimalist car kit or an overlanding kit, but in the shop a full run is hard to beat. If larger sizes are needed, non-ratcheting Snap-ons above 19 mm can fill that role, and a few Matco ratcheting wrenches reach up to 25 mm, though those are not reversible.

The Flank Drive Plus open-end design is the core of the appeal here, and the reversible ratcheting mechanism makes these wrenches genuinely fast to work with. In practice, not every size earns equal use. An 18 mm can go untouched if there are no 18 mm fasteners in your vehicles, and a 13 mm can occasionally be rare enough to make you think before packing it for a travel kit.

The set as covered here starts at 10 mm, but the smaller end is where things get interesting. Individual small wrenches in this line sell for roughly 48 dollars at the low end, with most between the mid 50s and the high 60s, so the 10-piece set is a serious investment rather than an impulse buy.

Snap-on 5.5 mm Flank Drive Plus Ratcheting Combination Wrench

Once you start building out below 10 mm, it cascades fast. Add an 8 mm and now there is a gap between 8 and 10, so a 9 mm follows. Then a 7 mm, and once the 7 mm exists, the 6 mm is inevitable. That little 7 mm would have been genuinely useful for years of racing bicycle work in the past, and even a 6 mm feels like it will find a purpose eventually.

The newest addition is the 5.5 mm, and at that size the Flank Drive Plus profile is barely visible on the tiny head. The honest justification is thin: some Toyota blower motor resistor screws do take a 5.5 mm, and it pairs with a small set of similarly tiny wrenches Snap-on sells separately. These small wrenches sell for a lot, around 44 dollars, and even with a discount that is a lot of money for a wrench you may rarely touch. Still, once you are this deep into the run, it belongs in the roll.

Buying Advice: Is the Full Run Worth It?

Filling out tool sets can spiral quickly. With sockets, you buy the 10 to 19 mm run, then need the 8 mm, then the 9 mm, then the shallows, the deeps, the semi-deeps, and then the question of quarter-inch versus 3/8-inch versus half-inch drive. It gets out of hand fast.

By contrast, these ratcheting combination wrenches offer a contained kind of disorder. A complete run down to 5.5 mm, with maybe one new small wrench added every few years, keeps the collection alive without the open-ended expansion of socket systems. If Snap-on released a 5 mm next, it would probably follow. A 20 mm on the big end? That is less where the appeal lies.

One practical note on mixing brands: filling missing slots in a Matco chisel and punch set with Mayhew pieces was an easy call, but the same logic would not apply to a set of Snap-on chisels, where matching the brand feels worth the premium. That same pull applies here. This current lineup represents what amounts to a complete set of these wrenches, all the way down to the brand-new 5.5 mm.

Conclusion

The Snap-on Flank Drive Plus reversible ratcheting combination wrenches are expensive, genuinely well-made, and quietly addictive. The 10 to 19 mm set is the sensible core for shop use, and the 5.5 mm is the charming indulgence at the very bottom of the range. If you already own part of this family and did not know the smaller sizes existed, consider this your warning: the run is easier to complete than it is to resist.