Aeroflow Performances Bellmouth-style velocity stacks are ideal for achieving maximum air velocity. Manufactured out of spun aluminium, these lightweight Bellmouth velocity stacks increase the volume or air at your compressor inlet. They come in polished and black anodized so they look awesome under the bonnet and you can chose between three sizes to meet your application needs. 3″ bellmouth has a 6″ (152.4 mm) O.D. so you can run an Aeroflow pod filter.