Quality sphygmomanometer for yourselfer.

As often with Park Tool, this tool is expensive. But it remains the cheapest sphygmomanometer I found on the market. Other products, professionals, are 3-5 times more expensive.
POSITIVE points:
(+) Used to measure the tension of bicycle wheel spokes, with the supplied table that converts the figure read on the tensiometer tension in kilogram-force (or Newton).
The conversion table covers round spokes or flat steel (stainless or not), aluminum round or flat, round or flat titanium, Mavic and SPO Spinergy.
(+) And calibrated Made in the US plant (St. Paul, Minnesota), this is not what's made in China. Immediate use.

Negative points:
(-) Can sometimes give slightly different results consecutive. This delta seems to be due to internal friction in the region of the reading area.
A light lubricating reading slit oil dry PTFE appears to suppress this phenomenon effectively.
(-) The European price.
Combined with a good centering wheel, good key rays, and you're ready to shine your wheels yourself or revealing in number.
For advanced amateur handyman.