... K55, N80, L80,P110 2.Thread: BTC,STC,LTC 3.Standard: API 4.Place of Origin: China 13 3/8" btc casing coupling ... Tubing coupling from 1.9” to 4-1/2”, Casing coupling from 4-1/2” to 13-3/8”TYPE: NUE, EUE (tubing coupling ... .459-5/8”BTC269.88*269.8823.1610-3/4”STC298.45*203.2020.7810-3/4”BTC298.45*269.8825.7411-3/4”STC323. ...