Have used this for ELR shooting and PRS, the attached retractable reel is to keep it from hitting the ground if dropped while trying to reholster but can be removed.
This works great for shooting the mile, can easily pick up a 20" gong at 1760+ yards. Have ranged deer over 1000 yards. The ballistics calculator is also a nice feature for quick shots in the field.
It's used so has some wear but the glass is perfect and functions flawlessly.