propane gas detector and plumbing vent

[trkr33]

say i have come to that time when my gas detector has lived it's life and i'm having to buy a new one, my question is mine is a safe-t-alert 30-441 which they have but i see a 40-442 and 30-442 so has anyone gotten one replaced with the 40-442 number is it better or just more money. i have found some on line for around $55 to $65 for the surface type that mine is as i'm not sure that i have enough space to use flush mount on mine because of keystone great lol design on side of cabinet drawers, also i have seen these tornado type vent pipe for my sewer vent but was wondering if anyone has used one of thoes solar type vent caps with the fan in it and was they worth the $25 bucks.

[path1]

On the safe-t-alert question I had the same questions but couldn't get answers on sizes so I took out the old one and got replacement the same size to put back in existing hole. And I actually read the info sheet on new one, which said to the effect...good for five years from date of manufacture listed on back. Which was already 1 1/2 years old when I bought it "new". Which means replace date is not purchase date. Maybe you'll get lucky or ask for a "fresh" one.

On solar sewer pipe vent question. IMO anything solar that is $25.00 can't be that good.