For 1" Tubing - Size: 331R Crimp Clamps | Description | SKU | Ear Width | Open/Close Range (mm) | Open/Close Range (inches) | ½” | 210R | 9mm | 18.2 - 21.0 | .72 - .83 | ¾” | 256R | 9mm | 22.8 - 25.6 | .90 - 1.01 | 1” | 331R | 10mm | 30.0 - 33.1 | 1.18 - 1.30 | 1 ¼” | 425R | 10mm | 39.4 - 42.5 | 1.55 - 1.67 | https://www.ndspro.com/331r-1-ss-pinch-clamp.html |