The problem it's built for
Mixer tap fixing nuts sit under the basin or sink, usually tucked behind the bowl where a standard socket or spanner can't get a straight run at them without pulling the fixture half apart first. The Plumtool Flexible Mixer Tap Driver Kit (FMTD3652, $110.90) solves that with a 3/8" flexible drive shaft that bends around the cabinet and cistern to reach the nut from an angle a rigid tool can't manage.
What's actually in the kit
The kit is built around one 3/8" flexible drive shaft (200mm long), a 3/8" hex adaptor (40mm long) for driving it with a standard ratchet or driver handle, and five extra-long 3/8" drive sockets covering 9mm, 10mm, 11mm and 12mm and 13mm. That five-socket spread is the part worth checking before you buy — it's sized to cover the common range of mixer fixing nut sizes across most brands, not just one.
Matching the socket to the fixing nut
Fixing nut size isn't standardised across every mixer manufacturer, so don't assume before you're under the sink. If you're ordering ahead of a job, check the mixer's spec sheet or measure an old nut if you're replacing a like-for-like unit. Carrying all five sockets in the kit means you're not stuck guessing on site — the point of the kit is covering the realistic spread, not just the one size you used last time.
The 10 Newton-metre limit — and why it matters
The flexible drive is rated to a 10Nm load limit. That's enough for routine tightening and removal by hand-feel with the driver handle, but it's a genuine limit, not a marketing number — lean on it harder than that (common with a seized or corroded nut that's been sitting for years) and you risk twisting or damaging the flexible shaft rather than shifting the nut. This is worth knowing before you reach for this kit on a nut you already expect to be seized.
Flexible driver vs basin wrench: which wins
A basin wrench gives you more raw leverage and is the better choice for breaking a genuinely seized or corroded nut free in the first place. The flexible driver kit wins once the nut is moving freely or on a routine install/removal where the problem isn't force, it's reach — tight cabinets, deep cavities, or an angle where a basin wrench's swing simply doesn't fit. Plenty of plumbers carry both: break a stuck nut free with the basin wrench, then finish the job with the flexible driver where a rigid tool can't reach. For other tools that round out a tap service call-out, see our Tap Service Kit guide and the Tap Flange Remover and Breech Straightener guide.
Frequently Asked Questions
What socket sizes come with the Flexible Mixer Tap Driver Kit?
Five 3/8" drive sockets: 9mm, 10mm, 11mm, 12mm and 13mm, covering the common spread of mixer tap fixing nut sizes across most brands.
What's the torque rating on the flexible drive shaft?
The flexible drive is rated to a 10 Newton-metre load limit — fine for routine tightening and removal, but not a tool for forcing a badly seized or corroded nut.
Should I use this kit on a seized or corroded fixing nut?
Not as the first tool reached for — a basin wrench gives more leverage to break a genuinely seized nut free. Switch to the flexible driver once the nut is moving, or for routine installs where reach, not force, is the problem.
Does the kit include a driver handle or ratchet?
It includes the flexible drive shaft, the hex adaptor and the five sockets — you drive it with your own ratchet or driver handle fitted to the 3/8" hex adaptor.