Seco - 2.5 inch Sliding Prism with Tilting Reflector (6455-00) deals with the signal frequency changing

with the signal frequency changing based on proximity to the object

The laser includes a battery level indicator

Model Number: B31022Y16

Presco Safety Skirt Perimeter Marker - Case of 25

while the HR320 is more basic and suited for general applications

Seco - 2.5 inch Sliding Prism with Tilting Reflector (6455-00) deals with the signal frequency changingSeco 2. 5 inch Sliding Prism with Tilting Reflector Model Number: 6455 00 Features: Use the 2. 5 inch Sliding Prism with Tilting Reflector with SECOs 5120 Series Geodimeter Style Prism Pole Includes a large 2. 5 inch (63. 5 mm) silver coated prism with protective rubber ring 0 (zero) offset Attaches to the bottom of the graduated section of the pole so heights can be taken close to the ground Large easy to use clamping knob Tilts in 15 increments,