Not a bad light but a terrible value - Steiner Laser Devices MK4 LED Tactical Weapon Light w/ TIR Lens

Steiner chose to go with a proprietary body size with the mk4, so kiss any after market mounts goodbye. The mount it comes with is adjustable, bulky, only allows you to mount at a 45°, and only works on 1913 picatinny rails. The mount is not a deal breaker but it is a significant consideration before purchasing this system. The tape switch works but I would not want it on a duty type rifle. The plug for the switch is very unsecure and can easily be removed from the tailcap inadvertently. The actual switch itself isn't much better. It is not very tactile and may not activate the light unless you hit the middle of the switch. Also, the switch attaches via velcro glued to your rifle. No rail mount, just a sticker. Mine moves around constantly and really doesn't stay in place. Again, there is no aftermarket support for the steiner mk4 switch. Finally, the performance is not great. Its far from bad but it under performs for the price point. It casts a very wide beam that fails to reach beyond 50meters. It is a durable light, I have had it next to a muzzle break for 5 years with no issues (beyond what was previously stated). Altogether, modlite and cloud defensive greatly outperform the steiner for a similar price with more modularity. Surefire is quality and beats the steiner for the price but they perform similarly. Arisaka makes some great budget options that outperform the steiner although may lack durability. The steiner would be highly recommended if it was $150 but at its current price point there are way better options.