Sigma Base 400 Wired Computer Refurbished. The Sigma Base 400 Wired Computer lives by the maxim less is more. If all you need are just the basic cycling functions such as speed, triptotal distance, and ride time in a tidy, compact package then this is the perfect solution. It's wired for superb reliability and is waterproof, too, in case you get caught out in the rain. Not only that, this model has been refurbished by the experts at Sigma Sports and is guaranteed to be 100% functional just like new!