![What is this knob at the top of my inflatable hot tub? It is not under the water when no one is in the tub. The hot tub is a Bestway SaluSpa What is this knob at the top of my inflatable hot tub? It is not under the water when no one is in the tub. The hot tub is a Bestway SaluSpa](https://preview.redd.it/what-is-this-knob-at-the-top-of-my-inflatable-hot-tub-it-is-v0-69rprzhd80g91.jpg?auto=webp&s=3f17297a35e1a098d93721596b529641f91e9515)
What is this knob at the top of my inflatable hot tub? It is not under the water when no one is in the tub. The hot tub is a Bestway SaluSpa
![Coleman 71-in x 26-in 4-Person Inflatable Round Hot Tub in the Hot Tubs & Spas department at Lowes.com Coleman 71-in x 26-in 4-Person Inflatable Round Hot Tub in the Hot Tubs & Spas department at Lowes.com](https://mobileimages.lowes.com/productimages/afdb3438-579d-44c0-a8e7-29c015b29bcf/60909129.jpg)
Coleman 71-in x 26-in 4-Person Inflatable Round Hot Tub in the Hot Tubs & Spas department at Lowes.com
![Amazon.com : Bestway SaluSpa San Francisco HydroJet Pro Inflatable Hot Tub Spa | Large, Square Portable Hot Tub with Cover | Features Filtered Heated Water System and 180 Jets | Fits 5-7 Amazon.com : Bestway SaluSpa San Francisco HydroJet Pro Inflatable Hot Tub Spa | Large, Square Portable Hot Tub with Cover | Features Filtered Heated Water System and 180 Jets | Fits 5-7](https://m.media-amazon.com/images/I/517ImpP7U2L.jpg)
Amazon.com : Bestway SaluSpa San Francisco HydroJet Pro Inflatable Hot Tub Spa | Large, Square Portable Hot Tub with Cover | Features Filtered Heated Water System and 180 Jets | Fits 5-7
![Oval Inflatable Hot Tub Spa With Drink Tray and Cover - 2 Person - 145 Gallon - Black and White - ALEKO Oval Inflatable Hot Tub Spa With Drink Tray and Cover - 2 Person - 145 Gallon - Black and White - ALEKO](https://cdn11.bigcommerce.com/s-f0xbps97iz/images/stencil/1280x1280/products/2571/65409/HTIO2BKW_3__76786.1649870724.jpg?c=1)