Does this chrono from RSOV.com look familiar? Though this one is rechargeable and must have been purpose-built for UK players (the plug). It doesn't seem to show balls per second though according to the specs... "A.C.M. reliable 'Speeder 558' Guarder type digital chronoscope (Guarder type) with built-in rechargeable battery comes with 220VAC UK charger. Easy to use showing either mps (meter per second), fps (feet per second) and joules (energy) of each bb shot."