22 inch rail holes, 25 1/2 inch overall width. Great condition, customer sold unit and got out of camping. Retail is $2600. Price is obo. Call Dan at 913-294-2733 with any questions, thanks!
 
"The TrailerSaver BD3 is the latest in air-ride technology from Hensley Mfg. The BD3 is designed to be taken apart in two pieces, for easy installation and removal. Fits standard slotted rails."