Weld Head offers scissors clamping mechanism.
Press Release Summary:

Original Press Release:
New Scissors Lock/6" OD Weld Head
6" "Scissors-Lock" Orbital Weldhead: Unique "Scissors" mechanism clamping provides excellent alignment and ease of use for precision welding of tube up to 6" OD. Other features indude heavy-duty construction making it ideal for site work, extremely reliable arc starting, and excellent gas coverage to ensure clean welds. Also available, micro-weld heads down to 1/8" OD and latest technology orbital welding systems to buy or rent.