Side by side.

Specification	DU-038 DU-038 Quote
Width	1.074"
Height	0.560"
Flange	0.250"
Material	Rubber
Type	Sponge
Durometer	2A3 (sponge grade)
Colour	Black
Mount	Push On
Bulb position	Side
Core	1in Wire

Spec sheets live on each part's page.