The RR 415 is DT Swiss's lightest offering in a traditional alloy rim. They reached the low 415 gram weight by using one eyelet instead of two. This nets a 50 gram per rim weight savings.
The rim itself is constructed from extruded 7000 series aluminum. The rim is this cut and welded together using DT's proprietary SBWT welding process. The rim is completely anodized and the sidewalls are machined for a flat, smooth and consistent braking surface. There are small drillings on the sidewalls so you can measure the amount of wear on the rim.
The 415 is 19.4mm wide and 20.8mm tall with an angled/rounded profile to provided improved aerodynamics and better handling in cross winds. The extrusion and all other rim fabrication processes take place right in the DT Swiss factory for ensured quality control.
Trained and raced on these for about 6 months with no problems. Laced to an old set of Dura Ace hubs. Spoke tension is intentionally a little low. Hubs were originally laced 3 cross but with the 415s I laced radial front radial left rear. I have read that changing from 3 cross to radial can cause flange cracking if you are not careful with spoke tension.
This is a nice, pretty light set of wheels. But the main reason I went with the 415s instead of the 465s is that it is so much easier changing tires on a single eyelet rim and the 415 looked to be the best single eyelet rim available.