Side by side.

Specification	SD-12109-OS SD-12109-OS Quote
Width	1.300"
Height	1.000"
Flange	0.300"
Material	Rubber
Type	Sponge
Durometer	2A3 (sponge grade)
Colour	Black
Mount	Push On
Bulb position	Side
Core	1.43in Wire
Industries	Emergency Vehicles

Spec sheets live on each part's page.