I was recently in need of an inexpensive VNA calibration kit with SMA connectors for use in an undergraduate teaching environment. While you can buy cheaper calibration kits many of these either don't have the coefficients that describe the standards available or if they do they don't seem to have been rigorously tested and verified. This is not the case with this calibration kit.
This is a kit that has been professionally researched and put together. I have used this on various VNAs ranging in cost from £10k to £250k (up to 7GHz only of course!). There's very little difference between the corrections derived from this kit and those of "flagship" 3.5mm/2.92mm calibration kits such as the venerable Keysight/Agilent/HP 85052B or Anritsu 3652 kits costing far more. Comparison was done using a HP 85053B verification kit and other Maury Microwave precision airlines.
This is an excellent value alternative to an calibration kit such as the Keysight 85033E (which costs10dB more!). At this price point I regard it almost as a consumable product as far as our teaching labs go. I have used three kits bought over a period of a couple of years and the results are very repeatable kit-to-kit. This is real testament to the effort Dr Kirkby has put into this. The inclusion of a verification device (and reference data) is an added bonus - anyone who has used a VNA knows its easy to kid yourself that your cal is good.
In summary, recommended to anyone with a VNA needing to measure SMA connector devices up to 7GHz.
Excellent kit to have in your lab if your uses are under 7GHZ even if you have expensive 3.5mm kits. This thing will last, it has good quality bits nice think coating, the case is super strong and so is the foam. The best of all is the customer support it has in case you need it you get help from knowledgeble people not just sales persons. The added attenuator can be used as a veification or for other purposes. The Price is just right for what you get.