FEP Supersound Teflon Caps

FEP Supersound cap, by SCR Made in France

Is anyone familiar with this teflon cap, supplied to me by Roger at Wyetech Labs as a replacement for the output caps in my Wyetech Opal? I have heard of VCaps and Auricap teflon caps, but not this one. Curious as to its quality and attributes. Thanks.