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Tubing Coupling
Pipe O.D. 1.900, 2-3/8, 2-7/8, 3-1/2, 4, 4-1/2 in
Grade J-55, C-75, L-80, N-80, C-95, P-110
Thread Connection EUE, NUE
Option Electro-zinc plated


Standard API 5CT, API 5B


Casing Coupling
Pipe O.D. 4-1/2, 5, 5-1/2, 6-5/8, 7, 7-5/8, 8-5/8, 9-5/8, 10-3/4, 11-3/4, 13-3/8, 16, 18-5/8, 20 in
Grade H-40, J-55, K-55, C-75, L-80, N-80, C-95, P-110, L80-13CR
Thread Connection BTC, STC, LTC
Option Electro-zinc plated


Standard API 5CT, API 5B


Coupling pipe grade identification by paint color
Grade Color Coding (Painted Outside)
H-40 Black
J-55 or K-55 Green
N-80 Red
M-65 or L-80 Red with one Brown Band
L-80 Type 9CR Red with two Yellow Bands
L-80 Type 13CR Red with one Yellow Band
C-90 Type 1 Purple
C-90 Type 2 Purple with one Yellow Band
T-95 Type 1 Silver
T-95 Type 2 Silver with one Yellow Band
C-95 Brown
P-110 White
Q-125 Type 1 Orange
Q-125 Type 2 Orange with one Yellow Band
Q-125 Type 3 Orange with one Green Band
Q-125 Type 4 Orange with one Brown Band

Couplings are short lengths of pipe used to connect 2 joints of tubing or casing.

They come with painted colour codes on their external surface to indicate their grades.

Couplings are manufactured according to API 5CT and 5B specifications.

Coupling Processing Diagram

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Why choose Lake Petro?
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Methods of Payment & Quality Control
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Buyer’s Guide

Please send us your inquiry with detail item description or with Model number. If there is no packing demand we take it as our regular exported standard packing. We will offer you an order form for filling. We will recommend you the most suitable model according to information you offered.

We can give you really high quality products with competitive price. We have a better understanding in Chinese market, with us your money will be safe.

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Lake Petro is located in Dongying City, which is famous for Shengli Oilfield and the largest manufacturing hub of petroleum equipment in China. Following the principle of “quality first, science and technology innovated, people oriented”, every Lake Petro person is sparing no effort to provide the customers with best products and services. Our products are based on advanced production line and testing equipment, our products are designed and manufactured according to certification of API, ISO, GOST, etc.