Overview Reviews Product Description The HS503CU is a 20mm micro optical sight designed for rifle and carbine applications. Features include Solar Failsafe, Shake Awake, 12 brightness settings, Holosuns Super LED with up to 50k hours battery life, and Multi-Reticle System. Product Videos Custom Field Product Reviews Write a Review Write a Review × Holosun Hs503cu Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Email * Review Subject * Comments *