Rules around adjustable clubs

[Jodrell]

As far as I was aware it's illegal to use adjustable clubs in competition. I'm thinking of things like that iron that can be set to about 30 different lofts, but if that's illegal, then why aren't all of the drivers and hybrids etc that have moveable weights, or the collars that let you tweak the loft and lie of the clubs also illegal. Is the rule written in such a way that it says something like the club can only be adjusted with/without the aid of a tool?!?

[cnosil]

13 minutes ago, Jodrell said:

As far as I was aware it's illegal to use adjustable clubs in competition. I'm thinking of things like that iron that can be set to about 30 different lofts, but if that's illegal, then why aren't all of the drivers and hybrids etc that have moveable weights, or the collars that let you tweak the loft and lie of the clubs also illegal. Is the rule written in such a way that it says something like the club can only be adjusted with/without the aid of a tool?!?

I’ll reference the USGA rules, but the R&A should be similar

https://www.usga.org/content/dam/usga/pdf/Equipment/Equipment Rules Final.pdf

All clubs may incorporate features for weight adjustment. Other forms of adjustability may also be permitted upon evaluation by The R&A or USGA. The following requirements apply to all permissible methods of adjustment:
(i) the adjustment cannot be readily made;
(ii) all adjustable parts are firmly fixed and there is no reasonable likelihood of them working loose during a round; and
(iii) all configurations of adjustment conform with the Rules.
During a round, the performance characteristics of a club must not be purposely changed by adjustment or by any other means (see Rule 4.1a(3) of the Rules of Golf).