The release of the SL stem brings Rotor’s unique stem design already being enjoyed by roadies to us mountain bikers. And it's all in the bolts, or DDT Evo Technology to give it its proper name. Dual-thread pitch design Torx bolts in the faceplate and steerer clamp allow, Rotor claims, for incredible and reliable tightening forces. Rather than a broad bolt head doing the clamping, the DDT bolts thread into both the faceplate and the stem thanks to a stepped diameter and different threads. You'll need to take a bit of care with installation, as the bolts must be partially threaded into the faceplate before attaching it to the stem, but not too far - they thread into the faceplate as well as the usual threads as you tighten.
The SL stem is available for 25.4mm bars and with a rise of 6º. The claimed 83g weight is for the 90mm option - 105 and 120mm models are also available.