Review on ☕️ Resilient French Borosilicate Coffee Machine by Steve Cooper

tl;dr: The inner walls of the cups are not airtight and can be broken by fluctuations in air pressure. the bottoms of the cups are already broken; the broken cup wasn't even used yet. The product arrived and I immediately washed (manually) after which I left two cups and used the other two for a pot of freshly brewed tea. Everything went smoothly there, the kettle poured surprisingly well when for the price I was expecting something like a leak/drip on the side. The only noticeable thing, which was alarming in hindsight, was some condensation under one of the cups and a wet bottom. Fast forward two days, I wash the teapot by hand, leaving the rest of the previously used cups on the sink (too lazy to wash them at this point) and brew the teapot, intending to keep the other two cups happy use sideboard. When I picked up one of the cups I was immediately concerned, I know I dried them out before putting them away but they seem to have water in them. I grab a towel and notice no change when I wipe the inside or bottom of the cup and find that there is moisture in it. I put the cup back on the counter and the bottom immediately shatters. Maybe it's a one off issue and a quality control issue as the other three cups seem fine, but broken glass is a serious problem and you don't want to deal with it. With. I definitely hope none of the splinters cuts me in the middle of the night when I'm less conscious. Bottom line: if you need this product, buy it for the teapot and discard the cups for your own safety.