The isolation is the best in spinfit. I had lot of issues with original earbuds of many iems like tin t4, they kept dropping out after a while. These buds fixed the isolation issue & they don't drop out at all. & due to the unique design you don't have to adjust angles of the iem for best isolation.
dunno if these are any good as product shipped, then was "cancelled" (?), was re-sent, then shipment disappeared. asked for refund.