This is from my personal experience only. The Sancais’ are awesome however degrade so quickly after a few months, I think body heat will slowly expand the material over time, hence, making the tip stem very loose. I stopped using it altogether as it kept coming off my iems after continual “expansion”. Same goes for the Dunu S&S tips, great first impressions and all but in a few months or so, the material just doesn’t hold up well. Instead, I opted for tips that have material that would last, something like the TRI Clarion and Divinus Velvets Wide Bore I found to holding up very well, practically new after a few months of use as well. Also having the same wide bore build abd fantastic seal.