Side by side.

Specification	SD-127 SD-127 Quote
Width	1.125"
Height	0.850"
Flange	0.200"
Material	Rubber
Second material	PVC
Type	Sponge
Durometer	80 Shore A
Colour	Black
Texture	Leather Grain
Mount	Push On
Bulb position	Side
Core	1.17in Stamped Steel

Spec sheets live on each part's page.