Sadly The Cartridge Man aka Len Gregory passed away nearly a year ago! So his products are no longer available.
I’ve auditioned the Soundsmith Strain Gauge 210 and yes it is very detailed and revealing, but the Koetsu Rosewood Signature that I use is also in a similar realm, so until it is time to renew I’ll stick with it, only then may I push the boat out and buy a Strain Gauge - as here in the UK it is considerably more expensive than in the US
I’ve auditioned the Soundsmith Strain Gauge 210 and yes it is very detailed and revealing, but the Koetsu Rosewood Signature that I use is also in a similar realm, so until it is time to renew I’ll stick with it, only then may I push the boat out and buy a Strain Gauge - as here in the UK it is considerably more expensive than in the US