Brand: ACDelco

Type: Iridium spark plug set for automotive engine ignition

Part numbers: 41-156 (ACDelco), OE/OEM 12683541 (GM)

Quantity: 4 spark plugs (4 pack) in individual ACDelco boxes within outer carton

Design: Iridium center electrode, threaded metal shell, white ceramic insulator with ACDelco branding, standard terminal end

Packaging: GM Genuine OE Original Equipment branding with multilingual "Iridium Spark Plugs" labeling

Color: White ceramic and silver-tone metal

Actual measurements: 6x4x4, 15oz (package dimensions and weight as written)

Keywords: ACDelco spark plug, iridium plugs, GM OE replacement, engine ignition, 41-156, 12683541