Side by side.

Specification	BL-045 BL-045 Quote
Width	4.360"
Height	1.550"
Flange	0.250"
Material	Rubber
Type	Sponge
Durometer	2A2 (sponge grade)
Colour	Black
Mount	Push On
Bulb position	Side
Core	SD-500L Spring Steel

Spec sheets live on each part's page.