Base unit consists of two 6" steel rods fixed to aluminum clamp heads
Rods have threaded end holes that accept the interchangeable brass tips or extension rods (included)
Three styles of tips included: ball tips for inside measurements, pointed tips for inside corner measurements and mushroom-shaped tips for outside measurements
Clamp heads have large thumbscrews that slide easily for quick adjustments
Two pairs of extension rods included: 4" and 12" allowing a maximum span of 44"
Additional 12" extensions available
Available 1-3/8" diameter mushroom-shaped tip provides larger reference face when hooking over edges for outside measurement and is reversible for inside measurements
With flat side out, provides stable platform for bar gauge when transferring vertical measurements