FerMonster Carboy - Replacement Lid O-Ring

FerMonster Carboy - Replacement Lid O-Ring

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Replacement O-ring for the Fermonster Plastic Carboy lids (all sizes use same lid).  

The o-ring is a little tricky to install so please be sure to watch our video in the video tab on how to install it. 


Item # FE251
Shipping Eligible for Free Shipping Program
Availability California - In Stock
Pennsylvania - In Stock
Weight 0.12 LBS
Community Q&A

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Browse 2 questions Browse 2 questions and 55 answers
Why did you choose this?
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backup part
nathan p on Jul 28, 2021
Gotta have it for the lid to work
Jeff S on Jul 22, 2021
backup part
nathan p on Jul 28, 2021
Just in case. For the future.
Adrian O on Jul 23, 2021
Gotta have it for the lid to work
Jeff S on Jul 22, 2021
safety redundancy
Greg B on Jul 22, 2021
Just in case.
Craig C on Jul 6, 2021
Old rings got stretchy and were no longer sealing
Daniel T on Jun 30, 2021
Good to have replacements
Gary N on Jun 11, 2021
Dirk L P on Jun 5, 2021
Its been over a year since I last replaced the o-ring
David T on Jun 2, 2021
Michael W H on May 15, 2021
Spares are important
Shawn M on Apr 23, 2021
FRANK M on Apr 22, 2021
for backup
Joel T on Apr 19, 2021
Just in case I damaged one I would have a replacement.
Joel Bornhoft on Apr 19, 2021
Eventually I might damage one .
James Duclos on Mar 31, 2021
My O ring is no longer able to form a good seal
Patrick C on Mar 31, 2021
Tom F on Mar 29, 2021
For backup parts
Todd F on Mar 25, 2021
Always good to have some spares
Dave A on Mar 24, 2021
Replacement parts
Nicholas G on Mar 9, 2021
I don't want to be without this when I wear out the o-ring that comes with the Fermonster.
Matt Burns on Feb 9, 2021
TomR on Feb 8, 2021
For new lids
Wayne S on Jan 30, 2021
Trauma Nurse on Jan 8, 2021
Customer service recommended
Richard B on Dec 23, 2020
always like to have a spare
Patrick M on Dec 23, 2020
Wanted to have some replacements on hand. I like the fermonster carboys but the sealing o ring is pretty small and delicate.
Ryan H on Nov 25, 2020
Good idea
bruce b on Oct 25, 2020
For my new lid
Timothy L on Oct 13, 2020
Can’t hurt to have a spare o ring
Blake F on Oct 6, 2020
just in case
Frank V on Sep 24, 2020
Just in case I need it in the future.
Felix B on Sep 24, 2020
Own one, it's good
Daniel R S on Sep 22, 2020
for backup.
Michael S on Sep 19, 2020
John L on Sep 17, 2020
Replace existing rings
Ray W on Sep 9, 2020
Always a good idea to have a spare
Jack G on Aug 11, 2020
Spare Parts
Greg Harrowsmith on Aug 11, 2020
Because the replacement lids don't come with one standard!?!
Chris J on Aug 5, 2020
need a spare just in case
Wayne S on Jul 28, 2020
Can't hurt to have an extra.
Ralph J on Jul 9, 2020
I'm probably gonna ruin the original
Chris M on Jun 23, 2020
May need
sean r on Jun 11, 2020
Better to have and not need than need and not have.
Douglas b g on May 21, 2020
Cause i need it
Daniel P on May 13, 2020
I have an o ring that is starting to show wear.
Michael J on May 9, 2020
o rings...
Lucas C on May 1, 2020
extra parts are good to have
Brian B on Apr 30, 2020
need it
batman on Apr 24, 2020
Replacement for a nicked original ring
Gregory G on Apr 7, 2020
Just in case. For the future.
Adrian O on Jul 23, 2021
safety redundancy
Greg B on Jul 22, 2021
Are these necessary it seems airtight without it?
Matt Mcdonald on Apr 30, 2018
BEST ANSWER: These are replacement/backup O-rings. The Fermonster ships with one.

4.7 / 5.0
6 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Rated 5 out of 5
Necessary items.
These are a must have, if you want your airlock to work. I enjoy the bubbles.
June 9, 2021
2 months ago
Rated 5 out of 5
Fits correctly and seals well.
March 3, 2021
5 months ago
Rated 4 out of 5
Works great just expensive for what it is.
May 3, 2020
over 3 years ago
Rated 5 out of 5
I bought this for a spare at my age it is easy to lose or misplace things I use.
February 12, 2019
over 2 years ago
Rated 5 out of 5
Ordered a couple to have on hand as these are small and thin and I'm sure will need to be replaced. The size if then though is odd as they are larger then ones I was finding locally so added them to order I was making to have extra of. Used originals now for a year and no issues.
September 10, 2018
over 2 years ago
Rated 4 out of 5
It takes a little mucking about to get the o ring in place but they do seal well.
June 26, 2018
over 3 years ago