When your tripod is not equipped with an accurate spirit level, this convenient plate fits between your BH-40 ballhead and your tripod platform and gives a true level reading for the base of your ballhead.
 
BH40-LVL features:

• Fits snugly between your BH-40 ballhead base and the tripod platform.
• Includes an accurate 15mm acrylic circular spirit level sensitive to 30 minutes of angle.
• CNC machined from 6061T aluminum.
• Individually calibrated on super-level granite surface plate.
• Degree marks on BH-40 panning base remain visible.
• Accommodates ballheads with base diameters no larger than 2.0" (50mm)
• NOT compatible with our BH-40 LR II ballhead (clamp is too large to clear the rim of the BH40-LVL when clamp is flopped over into the drop notch.