This RWS Thru Bolt w/Aluminum Lever is the latest version of DT's RWS technology. Where the standard RWS Thru Bolt uses a carbon reinforced plastic lever arm, you'll get a lever made from machined aluminum here. The weight is exactly the same, and you'll perhaps get more durability in the event of a crash with these alloy bits, not to mention the appeal of the more sculpted look.
RWS stands for Ratchet Wheelmounting System. It has the look of a quick release (minus the springs), but in place of a lever attached to a cam, there's a lever attached to a bolt head. Turn the lever clockwise to tighten. When there is sufficient resistance (15nm), stop turning. Press the red button to position the lever in a place where it won't get knocked around. You're done, and the benefits are pretty obvious. It provides up to 50% greater clamping force than with a conventional quick release, which can be a great thing when riding a disc brake in front as it will resist the twisting forces better. And, they make it super easy to pop your wheels off your bike. The oversized shafts are high-strength, light weight 7075 aluminum, as are the lever arms. Want it off? Just start turning the lever counter-clockwise to loosen.
The DT Swiss RWS Thru Bolt w/ Aluminum Lever is available to fit three hub configurations -- Front 9x100mm, Rear 10x135mm, Rear 12x142mm (Syntace X-12 type). The weights are as follows: 49g (front 9 x 100) 63g (rear 10 x 135.)