Master Plunger MP500-3 Heavy Duty All Purpose Plunger, Laundry Tubs, Bath Tubs, Kitchen Sinks, Garbage Disposal, Toilets Commercial & Residential Use. Equipped with Air Release Valve, Black

I have a kitchen sink drain with a pipe that does not have enough slope in it to prevent eventual repeated clogging. Over the years I have used over two gallons of Walmart's drain cleaner which always helps at least a bit but the drain just gets slow, over and over again. THIS device is what I needed - a toilet plunger did not help, it did not fit the drain opening well. The supposed open/closed 'valve' is not really that. What it really is, is a handle that threads onto the bellows section and it will leak air badly when you loosen it a bit but it leaks air much less when you fully tighten the threaded handle onto the threaded bellows part. It is possible to purge most of the trapped air in the pipe while the bellows are fully compressed, an accidental feature which let you have more suction on a vigorous up stroke. Then follow immediately with a forceful down stroke and repeat to loosen most stubborn clogs. I thought I'd need to run hot water first to soften up the clog but this worked like a champ on the first try! This is effective in part because the diameter of the bottom rings will mate with and seal against most sink drains to increase effective plunging power. They say this is recyclable plastic but I did not see any recycling code. Maybe I missed it?

Solved my clogged sink problem