Find Bar-Handle Screw Clamps, Bar Handle Nuts, Quick-acting Screw Clamps and Bar Knobs in this section of the Carr Lane catalog. Carr Lane’s Bar-Lok quick-acting bar clamps are the strongest on the market and accept all standard sizes of swivel feet. Extension nuts featured in this section provide excellent leverage and can be moved to any position for convenient tightening. Carr Lane Bar Knobs are made from heavy-duty cast-iron, that can easily be turned by hand and tightened by inserting a bar between the prongs. All Carr Lane Bar Clamps and Bar Knobs are available in multiple variations and sizes.