4mm is 4mm wide. If you would like it converted to another unit of measurement, please specify. Its equivalent in US Customary units is 0.157480316 inches or 0.0131233596 feet.
4 mm is 1/10 of 4 cm.
ø 21.21 mm 2.121 cm
1 mm = roughly 0.03937 inch (rounded)
About 1 3/8 inches. Direct Conversion Formula 35 mm* 1 in 25.4 mm = 1.377952756 in
1 mm = 4/100 inches