I have to say that the flameking refillable 1lb tanks are the greatest thing since sliced bread.
As for this refill adapter I have bought the kit from Amazon about 4-5yrs ago and never used it. Only because I have several FK 1lb tanks and bought direct the fork lift refill adapter. The reason was I wanted to keep the bbq tank for bbqs. And I didn’t have to turn the 40lb forklift tank upside down.
Always check for leaks. I have one 1lb tank that leaks with my torch but not with other products.
Go check your local propane dealers as they may have the flame king 1lb tanks but with their business brand on them.
I found one that was cheaper than online and was prefilled so I have about 5 not including the unused one.
This is worth it.