540nm is the wavelength of the green LED emitter in nanometers. The human eye’s peak photopic sensitivity — its maximum efficiency for perceiving light in daylight conditions — is centered around 555nm, in the green portion of the visible spectrum. A 540nm emitter falls close to that peak, in a range where the eye perceives the same light output as significantly brighter than a comparable red emitter at 650nm. In practical terms for competition shooting, a 540nm green dot appears sharper and more defined at a given brightness setting, and it maintains better visual contrast against a wider range of target backgrounds. This makes it faster to find in the window on the draw and faster to reacquire through recoil, which is the core advantage the HE407COMP-GR-6’s green LED delivers over a red-dot equivalent.

Memory Mode stores the last-used brightness setting in non-volatile memory. When Shake Awake activates the optic after a period of sleep — such as between stages, in a holster during the walk to the next bay, or during a cold start in the morning — the dot returns immediately to the exact brightness it was last set to. Without Memory Mode, some optics return to a default setting that may be wrong for current conditions, requiring the shooter to manually adjust before the stage. With Memory Mode active, the brightness is always where you last deliberately set it. For multi-stage competition matches where conditions change across different bays, or for duty use where the pistol may sit for hours before being needed, Memory Mode eliminates one more manual step from the ready-to-fire sequence.

At the distances where competition pistol shooting takes place — predominantly 5 to 25 yards for USPSA, IPSC, and IDPA — a 6 MOA dot subtends well under one inch of target. At 7 yards, 6 MOA is approximately 0.42 inches; at 15 yards, approximately 0.9 inches. On a standard IPSC A-zone or IDPA down-zero zone, a 6 MOA dot fits comfortably inside the scoring area at both distances. The speed advantage of a large dot — it enters your visual field immediately, requiring no hunting — is worth more at those distances than the marginal precision advantage of a 2 MOA dot. The Trijicon SRO 5 MOA has been a top production and carry-optics choice at the grandmaster level for the same reason. If your shooting also includes extended precision work at 25 yards or beyond, a 2 MOA dot is the better fit.

Both models use the same 407COMP platform: identical 1.1 by 0.87 inch window, 6 MOA dot size, RMR footprint, housing material, and battery. The differences are reticle color and price. The HE407COMP-GR-6 uses a 540nm green LED at $289.99; the HS407COMP-GD-6 uses a gold LED at $279.99. Green at 540nm is close to peak human daylight sensitivity, making it exceptionally fast to track in most outdoor and indoor lighting. Gold provides high contrast against warm-colored targets and bright backgrounds where red can wash out, and is accessible to shooters with red-green color vision deficiency. The $10 price difference is negligible for the reticle that best matches your specific lighting conditions and visual preference. Memory Mode is confirmed on both; the gold model additionally specifies Lockout Mode, which is not confirmed for the green.

The COMP suffix on both platforms means the same competition housing: the large 1.1 by 0.87 inch viewing window on the RMR-pattern footprint. The difference is the reticle system. The 407COMP (this optic) is a single-dot sight — it shows only the 6 MOA green dot with no switchable ring options. The 507COMP features the Competition Reticle System, which provides four independent elements (a 2 MOA center dot plus 8, 20, and 32 MOA rings) that can be configured in any combination. CRS shooters can run a large 32 MOA circle-dot for the opening stages and dial to dot-only for precision targets, all sharing the same zero. The 407COMP’s fixed 6 MOA dot is the simpler, faster-setup competition optic for shooters who do not need multi-reticle options and want a lower-complexity, lower-cost solution on the same window and footprint.

The HE407COMP-GR-6 uses a CR1632 3V lithium coin cell. This is not the CR2032 used in Trijicon RMR optics and many other pistol dots. The two are not interchangeable despite similar appearance. CR1632 batteries are widely available at electronics and hardware retailers. The side-loading tray allows battery replacement without removing the optic from the slide, and Memory Mode retains the brightness setting through a battery swap so no reconfiguration is needed after changing the cell.