Berntsen offers the following styles of bronze concrete survey markers for use in concrete or rock:
"C" style (US Army Corps of Engineers Type 1 Disc) has the classic 3" (76mm) long split-style tapered stem. It is available in 3-1/2" (89mm) or 4" (102mm) diameters. Orbital formed from solid unleaded silicon bronze bar.
For smaller marks use the "CD" style 2" (50mm) diameter marker has a 3 /4" (19mm) diameter x 2" (50mm) long stem and is notched to hold firmly in concrete or rock. Orbital formed from solid unleaded silicon bronze bar. It is also available as a leveling mark with a raised datum point (with recessed center) for precise monitoring (model CD2LB).
The "RT" style is a variation on the concrete disc theme and is available in a 3-1/2" (89mm) diameter. The RT1 offers more resistance to twisting and features four legs. Orbital formed from solid unleaded silicon bronze bar.
For C1 and CD2 installation instructions Click Here
For RT1 Rock Tablet installation instructions Click Here