Have now put together my quiver of Slake MDMs 430, 460, 490/500 520/530, and 40 extender - thanks Brett

I am a longtime fan of these masts - but not sponsored, so this is not a paid plug

Diameter is 42mm, they run on RDM extension using the shim - I have gone medium flex for all parts, but you can customise everything to your sail profiles etc

I have never liked the wet noodle feel of RDMs in cammed/performance sails, especially with my 95kg, so the MDMs are ideal, offering -

SDM stability, windrange, and flex feel
RDM smooth rotation, strength and reliability - see wall thickness compared to APEX 430 RDM

A few years back I was an involuntary crash test dummy in Slake R&D trials - on the foil with 9.0 I was run down by a clueless speed boat - SO lucky not to be seriously injured .... sail was a writeoff, boom twisted and snapped front end rope, but the SLAKE SDM mast held up through all of that and kept going strong for years! what can I say ... MDMs will be stronger again

All sessions so far the masts feel rock solid with various foil sails, even way overpowered, and pump sweetly, hope to try the 430 out with MACH sails soon on the next Primbee fin day

They sound a lot like my 90s kilwell matrix 5s. I've had them polevolted into the reef, boards dangling from them waves washing over, torn too many harneses ropes, smashed so many booms, but my 90s masts just keep going.
Interesting they use an RDM extender with shim. I'm still using ancient 42mm extenders from the dark ages, I'll have to see if I can get hold of those shims

Just went to their website to see if they sell the RDM mast extension converter.
Was very surprised to see they claim to be the World's first MDM.
They obviously didn't research that statement very well.
I've had my Kilwell Matrix 5s since the mid 90s

Bit disappointed to see their smallest is 4.0 I have a sail that needs a 3.4, and another a 3.7

Mike there website doesn't list everything, I had my 430 mast done as a MDM but for my smaller sails below 6.3 Slake produced a 400 RDM which is not listed on the site, I'm sure they'll do smaller masts

I guess they do say custom masts.

I also used to think that a 460 RDM was too noodly for my Flyer 7.0, until I got a NoLimitz FAST 460 RDM. Wow. Huge difference.

Old 4-batten Flyer 7.0 rigged on a 430 RDM. The new 5-batten Flyer 7.0 also rigs on a 430 RDM, but it is much better on a 460 RDM, especially the FAST.

PS the SLAKE MDM masts run on SDM cams (with my Severnes) - just tweak spacers and battens to your preferences

(Severne) RDM cams would be too narrow I think - but might work for some cams/brands .....??

Brett/Grae @ SLAKE can advise