Door handle material: High-quality ABS plastic with a chrome finish. To fit an open hole of 6 mm to 20 mm minimum diameter in your glass, it can be used on most glass doors at home or in the office. DIY replacement: This DIY replacement door knob is easy and convenient; you simply turn the two knobs by hand to replace the existing knobs on your glass doors. Package contents: 2 pairs of round door knobs (2 pairs = 4 knobs).