hi there - I think Paiste Wiki answered my question - judging by the pics and the weight, it seems as if it is a 24" medium!
Group: Crashes
Type: Medium
Size: 24 Inch
Series: Formula 602
Weight: 3408g (Pre-Serial), 3474g (Pre-Serial), 3509g (1974 Serial Number), 3600g (Black Label)
Years of production: 1959 - 1994
Sound file: Formula 602 24" Medium
Paiste's Description: <<< - >>>
Review: Weighing in at a lovely 3474 grams, this 602 plays like a beautiful slightly DRY Medium Thin to Medium 602 Ride! What's interesting about this specific 602 the initial attack has a slightly chime-like quality that is followed by a fairly dark, and controlled wash. I would not call this cymbal dry, however it does have a great stick definition that rides on top. The bell is medium low in pitch and solid. And of course it has that inimitable CLEAN sounding, clear, focused, articulate Paiste 602 tone-with all the mellowness of a 40-50 year old cymbal.
Slightly dry, focused, super mellow, articulate, subtle airy Vintage 602 tone. And with a plain that big it's a joy place your stick anywhere on it. You can really draw the sounds out.
Nothing sounds quite like it. NOTHING!!!
It's 2 feet of felicity!
This Paiste PreSerial 602 24" Ride can be used on ANYTHING! Rock, funk, pop, classic rock, punk, country, big blues, or jazz, use it ANYTIME you want to make a statement-whether bold or implied.
Review written by Hazelshould