According to different situation,the appearance can be dealed with eopxy powder,hot-dipped zinc,paint,dacromet or as your requirement.

Nominal diameter(mm)	measurement outside pipe(mm) D*d	rated preasure(mpa)	L(mm)
65*50	76*60	2.5	90
80*50	89*60	2.5	94
80*65	89*76	2.5	94
100*50	114*60	2.5	104
100*65	114*76	2.5	104
100*80	114*89	2.5	104
125*50	140*60	2.5	122
125*65	140*76	2.5	122
125*80	140*89	2.5	122
125*100	140*108	2.5	122
125*100	140*114	2.5	122
150*50	165*60	2.5	142
150*65	165*76	2.5	142
150*80	165*89	2.5	142
150*100	165*108	2.5	142
150*100	165*114	2.5	142

Nominal diameter(mm)	measurement outside pipe(mm) D*d	rated preasure(mpa)	L(mm)
150*125	165*133	2.5	142
150*125	165*140	2.5	142
200*100	219*108	2.5	179
200*100	219*114	2.5	179
200*125	219*140	2.5	179
200*150	219*159	2.5	179
200*150	219*165	2.5	179
250*100	273*114	2.5	215
250*125	273*140	2.5	215
250*150	273*165	2.5	215
250*200	273*219	2.5	215
300*100	325*114	2.5	245
300*150	325*159	2.5	245
300*150	325*165	2.5	245
300*200	325*219	2.5	245
300*250	325*273	2.5	245