If you're looking to build a super-light project bike, a full titanium cassette is a must-have. Its teeth have the same Ultra-Drive profile as the Steel/Ti cassette so you'll get the same precise and smooth shifting you expect from Record. 156g. Please note that Campagnolo packages these cassettes without a locking, and rather supplies them along with their wheelsets. If you don't have a spare lockring, don't forget to buy one.