PZLife 2-in-1 Water Bottle Brush Set, Water Bottle Cleaner & Straw Brush Cleaning Scrubbing Brush 15 in Long Bottle Brush Detachable Head Multi-Function Cleaning Brush Homework Cleaning Brushe

My vintage/ antique thermos is 12.1" and tall, the opening (measured on screw-in lid) is 1 inch (2.5cm). Narrower than it looks in the photo - the actual opening is narrower than the outer rim. Brush fits in with a little pushing, and the handle is long enough to reach and clean the bottom of thermos easily. Also great for cleaning cups and glasses etc. Base is plastic, rest of handle metal. Base seems to lock in firmly to the handle, feels strong while in use. I haven't tried the bigger brush head yet but it looks and feels like the same quality. The lock mechanism is plastic, so will probably wear out eventually, but overall this seems well-constructed.When attaching the brush head into the handle, be sure to TURN the brush head to LOCK IT IN PLACE!Otherwise it will detach and be stuck inside your narrow-neck container when you try to pull the brush out. Ask me how I know! I finally managed to pull the brush head out of the thermos by using a pair of needle-nose pliers. Would never have been able to get it out of a bottle with a long neck without breaking the bottle.This brush WILL spray all over when you pull it out of a narrow opening! Just cover with a dishcloth or point it down toward the sink.This brush is so much better than the ones that have a twisted wire stem holding the bristles in place. Those have little or no bristles at the tip of the brush pointing down, so can't clean the very bottom of the thermos or bottle, plus the wire tip often scratches the bottom. This brush has plenty of bristles pointing down as well as to the sides. They seem like good quality bristles, firm but not stiff. Great for general cleaning. They will not scrub out caked-on hard stuff, you need to soak the container in soapy hot water overnight, empty, and then put baking soda or something like that in before scrubbing.This fits into containers with an opening down to an inch wide, but not much smaller. (I tried it on a bottle with an opening only 3/4" wide, and it wouldn't fit - the black base of the brush-head might be that narrow, but the bristles won't allow it to fit.)

This is the best brush I’ve used for my glass water bottles due to the sturdy handle!

Nice brushes, work great.

Edit... After about a month the large bottle brush head snapped off leaving the plastic component in the handle so unable to remove and switch even to the smaller brush. Disappointed as I really liked these brushes! Sent back for refund.7 out of 5 stars. This brush is amazing! Gets all the bottle clean from top to bottom, the bigger head fits in both sizes of my bottle and plenty of handle room to work with. Sturdy product. Super happy I purchased it.

Works great for cleaning Swell bottles and other containers with small necks. Have only used once so far, but seems good quality. Very pleased with this purchase.