Stair Tread Gauge

Known as a 'spider' this useful dimension taker and checker is useful for numerous applications because it can establish the relative locations of 6 respective points in any structure.

Locked with a wing nut and supplied in a wooden box.
Callipers 2 x 600 mm; 2 x 800 mm; 2 x 1000 mm.

910 g, Overall length 1000 mm.