Dear sir:
We can supply following size coupling which is suitable to API standard casing&tubing pipe

Size	Spec	OD mm	Min length		Bore mm	Support width mm	Weight kg
	OD mm		Short coupling	Long coupling			Short coupling	Long coupling
4-1/2	114.3	127	158.75	177.8	116.68	3.97	3.62	4.15
5	127	141.3	165.1	196.85	129.38	4.76	4.66	5.75
5-1/2	139.7	153.67	171.45	203.2	142.08	3.18	5.23	6.42
6-5/8	168.26	187.71	184.15	222.25	170.66	6.35	9.12	11.34
7	177.8	194.46	184.15	228.6	180.18	4.76	8.39	10.83
7-5/8	193.7	215.9	190.5	234.95	197.64	5.56	12.3	15.63
8-5/8	219.08	244.48	196.85	254	223.04	6.35	16.23	21.67
9-5/8	244.48	269.88	196.85	266.7	248.44	6.35	18.03	25.45
10-3/4	273.05	298.45	203.2	273	277.02	6.35	20.78	28.2
11-3/4	298.45	323.85	203.2	273.05	302.42	6.35	22.64	29.84
13-3/8	339.72	365.12	203.2	273.05	343.69	5.56	25.66	33.08
16	406.4	431.8	228.6	298.45	411.96	5.56	34.91	42.33
18-5/8	473.08	508	228.6	298.45	478.63	5.56	54.01	61.43
20	508	533.4	228.6	298.45	513.56	5.56	43.42	57.04

Size	Spec	OD W mm	Min length NL mm	Bore Qbmm	Support width b mm	Bf mm	Weight kg
	OD mm
1.05	26.67	33.35	80.96	28.27	1.59	30	0.23
1.315	33.4	42.16	82.55	35	2.38	37.8	0.38
1.66	42.16	52.17	88.9	43.76	3.18	47.17	0.59
1.9	48.26	55.88	95.25	49.86	1.59	52.07	0.56
2-3/8	60.32	73.02	107.95	61.93	4.76	66.68	1.28
2-7/8	73.02	88.9	130.18	74.63	4.76	80.98	2.34
3-1/2	88.9	107.95	142.88	90.6	4.76	98.42	3.71
4	101.6	120.65	146.05	103.2	4.76	111.12	4.35
4-1/2	114.3	132.08	155.58	115.9	4.76	123.19	4.89