Side by side.

Specification	SD-12638 SD-12638 Quote
Width	1.620"
Height	0.825"
Flange	0.660"
Material	Rubber
Type	Sponge
Durometer	2A4 (sponge grade)
Colour	Black
Mount	Push On
Bulb position	Side
Core	2in Wire

Spec sheets live on each part's page.