The unit features splined ends with 1-1/4" serration for secure attachment. 16" of 3" 4130 tube which will give you a max width of 21.688" center of arm to center of arm, with 35103 bearings, and 5" arms (p/n 12011). If custom width is needed, please call for availability. Linkage kit (part number 35110) sold separately. 
 
Manufacturer: Mark Williams Enterprises, Inc.