Union connectors in tinned copper is used to splicing air line Minimum voltage. They come standard length and length heavy duty. Standard

Dimension in (mm)		Weight unit. aveg. lb (kg)	Interior Diameter in. (mm)
L	D
1 3/4 (44,45)	13/16 (20,64)	0,020(0,01)	0,198(5,03)
1 3/4 (44,45)	13/16 (20,64)	0,026(0,01)	0,246(6,25)
1 7/8 (47,62)	7/8 (22,22)	0,04(0,018)	0,306(7,77)
2 (50,8)	15/16 (23,81)	0,065(0,029)	0,443(11,25)
2 1/8 (53,98)	1 (25,4)	0,094(0,042)	0,490(12,45)
2 1/4 (53,98)	1 1/16  (26,97)	0,12(0,054)	0,595(15,11)
2 3/8 (53,98)	1 1/8  (28,58)	0,17(0,077)	0,700(17,78)
2 1/2 (63,5)	1 3/16 (30,16)	0,31(0,14)	0,762(19,35)

Heavy service

Dimension in (mm)		Weight unit. aveg. libras (kg)	Interior Diameter in. (mm)
L	D
2 3/8 (60,32)	1 1/8 (28,58)	0,03(0,01)	0,198(5,03)
2 3/8 (60,32)	1 1/8 (28,58)	0,03(0,01)	0,246(6,25)
2 7/8 (73,02)	1 3/8 (34,92)	0,06(0,027)	0,358(9,09)
3 1/8 (79,38)	1 1/2 (38,1)	0,09(0,04)	0,443(11,25)
3 3/8 (85,72)	1 5/8 (41,28)	0,15(0,068)	0,547(13,89)
4 1/8 (104,78)	2 (50,8)	0,25(0,11)	0,650(16,51)
4 3/8 (111,12)	2 1/8  (53,98)	0,37(0,17)	0,762(19,35)
5 1/2 (139,7)	2 11/16 (68,26)	0,78(0,35)	0,923(23,44)