Bought these many years ago. I was trying to get kits for NSR MC21 carbs.I went thru a local vender after showing him the ''parts-diagram'' for our NSR carburetors. These are two kits in sealed slip , never having been opened.The ''rubber-Shaped-O-ring'' is similar in shape as well as the bowl base gasket as our NSR OEM carbs.There are many small parts included as well.For some reason , that I really don't recall ,I did not ever use them? There is a part # on package #018-866 Qty 2 , No Manufacturere's name brand. I remember paying some hide ous Price of like $ 60-80 US dollars way back then.They were/ are for Khein carbs If memory serves correct. If someone can use them , Tell me what they are worth to you , plus shipping. Shouldn't be more than a couple bucks. Contact me for picture or additional info. Dave in CA