I use the green eBay bridge in my 3GHz VNA and it works very well. up to 3GHz
Color is not everything.. for examples:
* this probably good blue bridge is for sale on eBay by transverters-store:
If buying again, I would probably pick that one..
The seemingly most common green bridge has "www.60dB.com" lettering,
and its presumptive designer also sells on eBay:
They also sell a shielded version:
Both of the above vendors are based in Ukraine.
Owen Duffy reviewed a 60dBm.com unit,
but which vendor he used is unclear,
since he allowed that his may be a clone.
Another green bridge has substantially different construction, e.g.:
This listing interestingly includes AV3656B screen shots,
so arguably returnable if received item cannot match those results,
but lacks an SMA port for reference...
Oristo