P15D-25-1 base. Dual filament, up to 950 Lumens per each filament. 12 Volt non polarity works either positive ground or negative ground. Uses 60 5730 smd leds. Up to 57 to 67 Watt incandescent equivalent. The leds are aligned with your reflector for maximum light output. Dim-able with a variable DC supply such as a dimmer switch. Available in white 6000K and warm white 3000k. Extended warranty, please see detail page for more information. Maximum overall length is 1.944 inches. The maximum diameter is 1.058"