You've chosen a light that uses Surefire Scout tailcaps, right? This includes the Arisaka 18650 Series, 18350 Series, 600 Series, and 300 Series. Also the Modlite PLHv2 and OKW.
Now it's time to choose a tailcap. While it may seem like there are a lot of options, it's not as complicated as you think. There are five basic options, and then a few variants which include one of the five tailcaps.
- Arisaka Momentary
- Surefire Z68 Clicky
- Surefire UE socketed tailcap
- Surefire DS socketed tailcap with clicky
- Unity Gascap USB-C tailcap with clicky
Arisaka Momentary: This is our own custom tailcap which offers momentary only operation. Press and hold the light for it to be on. Release for it to turn off. In a pinch you can go constant on by threading the tailcap in until it stops, which will lock out the operation and hold the light on until you unthread it. The Momentary tailcap is supposed to be unthreaded slightly during normal operation by design - this is how you tune the amount of motion the button has, and how sensitive it is.
Surefire Z68 Clicky: The classic clicky tailcap. The Z68 offers momentary operation with a slight press on the button, and then will click to constant on if you press it a little further. Press it again to turn the light off.
Surefire UE: This is the cheaper socketed tailcap option which must be paired with a remote switch. Surefire offers the UE with their ST07 basic tape switch as the UE07 or with their much nicer SR07 switch as the UE-SR07. The SR07 will clip onto a picatinny rail and provides a separate momentary switch and clicky switch on the same unit. The UE tailcap will also work with the Surefire SR07-D-IT and Unity TAPS dual switches, Modbutton Lite and Unity Hot Button remote switches.
Surefire DS: This tailcap option has a socket for a remote switch plus a small clicky switch that can be used as a backup in the event your remote switch fails. Surefire offers the DS with their ST07 basic tape switch as the DS07 or with their much nicer SR07 switch as the DS-SR07. The SR07 will clip onto a picatinny rail and provides a separate momentary switch and clicky switch on the same unit. The DS tailcap will also work with the Surefire SR07-D-IT and Unity TAPS dual switches, Modbutton Lite and Unity Hot Button remote switches.
Unity Gascap USB-C: This tailcap has a USB-C socket for a remote switch plus a clicky switch that can be used as a backup in the event your remote switch fails. It is compatible with the Modlite Modbutton Lite USB-C remotes and Unity AXON and AXON SL USB-C remotes.
When choosing your tailcap you need to consider where you prefer to run the light. If on the same side as your support hand on the handguard, you'll be looking at the Arisaka Momentary or Surefire Z68. This makes for easy activation with your support hand thumb while comfortably holding the rifle. However, more and more serious users have begun to prefer to keep the support hand side of their handguard clean and put the light on the opposite side of the rifle while using a remote switch on the top rail. In this situation you'll be selecting a Surefire UE or DS tailcap and then the remote switch of your choice. A few examples that we prefer:
- UE-SR07: This is the Surefire UE socketed tailcap with SR07 switch. We consider this the best cheapest option since it's only a little more than the UE07 but the remote switch is much better since it can clip directly to a picatinny rail and offers both momentary and constant on.
- DS-SR07: This is the Surefire DS dual tailcap with SR07 switch. The feature set is the same as the UE-SR07 but you also get the backup clicky switch on the DS tailcap. The DS tailcap is highly recommended for duty use rifles.
- Modbutton Lite: You also need a DS or UE tailcap to utilize this switch. We love these - they're not too expensive, clamp directly to picatinny rails or m-lok with a cheap adapter, and there are a bunch of aftermarket mounts for different placement options like the Driven Arms MBL Dangler. Small, low profile, and reliable. Momentary only. These are now available with USB-C for use with the Unity Gascap USB-C tailcap.
- Unity Hot Button: You also need a DS or UE tailcap to utilize this switch. The Hot Buttons work like a Surefire Z68 so you get momentary and constant on operation for the Surefire plug versions, while momentary only for the laser versions. They are available for picatinny or m-lok, and angle the button at 45 degrees for better ergonomic use. We highly recommend selecting the Axon or Axon SL over the Hot Button.
- Unity Axon SL: You also need a DS or UE tailcap to utilize this switch. The Axon SL is an updated version of the single lead Hot Button, and work like a Surefire Z68 so you get momentary and constant on operation for the Surefire plug versions. The laser versions are momentary only. They are available for picatinny rails, and angle the button at 45 degrees for better ergonomic use. These are now available with USB-C for use with the Unity Gascap USB-C tailcap.
- Unity Axon: You also need a DS or UE tailcap to utilize this switch. The Axon is an updated dual lead version of the Hot Button. They are available for picatinny rails, and angle the button at 45 degrees for better ergonomic use. These provide two leads and two switches, one for Surefire UE and DS tailcaps, and one for lasers. These are now available with USB-C and laser leads for use with the Unity Gascap USB-C tailcap.