Hi Jerome
Pentax tech support says 49mm. Pentax website says 43mm... Boz: 43mm... B&H: 49mm.... (d'oh!)
Here BH says 43mm...
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=99752&is=REG
but... um... I guess I can just measure it, huh?
Indeed, you should measure it and get a definitive answer.
If you need the UV only, I wouldn't mind breaking a set. I don't really need a UV. I use the 43mm SMC filters on a 1957 Olympus Wide-S rangefinder with a fixed 35mm f/2 lens.
Andre
