Dispersion: 180°
Back is round, not flat
1/Pack
Please choose your diameter from the drop down menu.

The 4mm size does come with a red LED that can be powered with 6-12 volts.
Includes resistor for scale luminosity in 12 volt systems (to install the resistor, solder it into the positive side of the light as shown here). The 7mm and 10mm sizes do not include bulbs but can be fitted with a clear bulb found here: RO10
NOTE: the above bulbs will not fit the 5mm lens

Here are the dimensions for the available sizes, the "r" dimension is the bulb insert through the base of the fixture.

4mm Size: R=5/32" (4mm) H=7/32" (5.7mm)

5mm Size: R=3/16" (5mm) H=9/32" (7mm) r=1/8" (3.3mm)

7mm Size: R=9/32" (7mm) H=11/32" (9mm) r=3/16" (4.5mm)

10mm Size: R=3/8" (10mm) H=15/32" (12mm) r=1/4" (6mm)