Rivon U4 Pro Plus Review: A Titanium EDC Carabiner with Locking Knife and Screwdriver

Introduction

Rivon has updated its line of titanium EDC carabiners with the U4 Pro Plus, the latest step in a short but genuinely inventive product family. The original U4 stood out with a dual-clasp design: one clasp for things that stay attached, like keys, and another for hooking the whole unit onto different gear. It also carried a size 11 surgical steel scalpel blade, was full titanium apart from that blade, and shipped with spare blades that are easy to swap out. That last detail matters for air travel, since removing the blade leaves you without a knife in your bag while still keeping the carabiner useful.

Who the U4 Pro Plus Is For

This is a tool for people who like carrying something small that quietly solves a lot of moments. You may not think you need a knife and screwdriver on your keyring, but once you carry one you keep finding uses for it. The U4 Pro Plus suits commuters, travelers who fly and need to remove the blade, and anyone who appreciates well-thought-out titanium gear.

How the Design Evolved

The original U4 had the scalpel blade but no other tools, and the longest ruler at 4 cm. The U4 Pro kept the knife and added a screwdriver on the opposite side. That screwdriver has its own locking mechanism: press the small button to release, then fold it out. It uses a reversible bit with a little slotted driver on one end and a little Phillips on the other, held in place by a magnet. The magnetic holder works best with a double-sided bit oriented magnet-side down; other 4 mm bits fit too, though longer ones may sit differently. Adding the screwdriver also forced the ruler to shrink to 2 cm.

Main Strengths

The headline feature of the U4 Pro Plus is locking on both sides. Press one button to release the screwdriver, and a separate button locks the knife in place, both open and closed. The knife locks only when fully extended, which makes it feel far more secure in use than a friction-fold blade.

The other strength is the shared internal spring design. Because both tools use one common spring, you cannot depress the screwdriver release while the knife is partially deployed, and vice versa. Each tool must be fully open or fully closed before the other can be released, so you can never end up with both tools halfway out at the same time. It is not clear whether that was intentional, but it works as a welcome safety feature, especially compared with the classic half-closed-blade mishaps people associate with multi-tools.

Things to Consider Before Buying

A few practical points are worth weighing. The blade is a size 11 surgical scalpel, which is extremely sharp but small, so it handles fine detail work rather than heavy cutting, though spare blades are inexpensive and simple to replace. The screwdriver is designed around its own double-sided bit, so carrying an alternative 4 mm bit means accepting a slightly different fit or modifying the bit so it slides in further. And if you fly, remember to remove the blade before heading to the airport.

Buying Advice

If you already own the original U4 or the U4 Pro, the Pro Plus is the version that finally answers the obvious question: why lock the screwdriver but not the knife? With locking buttons on both sides, the shared-spring interlock, and the retained compact 2 cm ruler, this is the most complete version of the concept so far. If you fly regularly, keep spare blades at home and pop the blade out before travel; the tool remains useful without it.

Conclusion

Rivon’s small titanium carabiners are fun, but they are also genuinely practical, and the U4 Pro Plus is the strongest iteration yet. A locked scalpel blade, a magnetic reversible screwdriver bit, and an interlock that prevents two half-deployed tools at once add up to a keyring tool you will reach for far more often than you expect.