API 5CT crossover API 5CT crossover Standard: API SPEC 5CT Available in a wide range of sizes, weights, lengths and grades with any combination of connections.a. Diameters – 2 3/8” to 7”b. Weights - As Per API-5CT.c. Lengths - Any length.d. Grades - J-55, K-55, N-80, L-80, P-110e. Connections - EUE, NUE, STC, LTC, BTC API 5CT crossover