CR computers are very popular with pleasure and professional pilots. They solve T/8/D and wind triangle problems for light aircraft as well as those which approach Mach 2 speeds. Corrections for errors of compressibility and temperature rise are computed with ease. The wind solution is displayed graphically using the small back-side discs. Each computer comes with a fully illustrated manual.
CR-4 4-1/4" dia. (same as Jepp CR-2); vinyl. Standard model used by the military.
Excellent product! The wind calculation grid is especially helpful and some will make use of the sine calculator for calculating climb/descent angles. I've used other makes and models, but the APR version has lasted the longest.