28mm inlet claimed and all aluminum. If you're hoping to easily fit this, make sure your exhaust is 28mm OD. It will not weld to most exhausts as they are typically steel and the two have different metallurgical properties. I attached with steel epoxy and coated with aluminum solder. I'll clarify efficiency [or lack thereof] for $28, it's a piece of metal that attaches to an exhaust pipe.
HIWUP Black Disposable Face Masks 100 Pack - 3 Layer Protective Masks for Adults and Teens - Boxed Face Mask for Women and Men - Premium Quality Disposable Masks
5 Review
🏍️ Balaclava Face Mask - Lightweight Summer Motorcycle Ski Mask for Men & Women with UV Protection - Breathable & Durable
4 Review
3-Pack Lycra Bandana Face Hat for Outdoor Airsoft Motorcycle Ski Mask Winter Sun Balaclava Black Tactical Hood Helmet
8 Review
❄️ Winter Ski Mask - Unisex Balaclava Face Mask for Cold Weather - Ideal Gear for Snowboarding, Skiing & Motorcycle Riding (Black)
4 Review