Originally Posted by Farnsworth
... The Denso fits tighter on the center tube because the plastic end caps go in further on the ST, leaving a gap. ...
Nearly all cartridge with end caps and no center tube (other than the one in the housing cap) leave that radial gap between the media and the center tube, as far as I've seen. Some leave a larger gap than the ST, so much that the media is not effectively supported against inward collapse under pressure.
