More probe fodder - ruby/ceramic stylus from AliExpress

Given the recent probing activity, I finally got round to obtaining some spare tips for my Renishaw probe. For simplicity, I chose to go with styli of the same size as the one that came with the probe, namely:

• M4 thread
• 6mm ruby ball
• 50mm length (to centre of ball)
• Ceramic shaft (5mm dia)

After a bit of buggering about I found some on AliExpress for ~£30 each. Ordered a couple and they arrived today. Ordered on 19th April, so took 3 weeks to arrive.

They look OK. Unless they are grossly non-spherical or made of plastic, what could go wrong here? You have to dial them in to remove any runout, regardless of where you buy them and the other dimensions and materials look pukka. 

Here's one of the new styli alongside the original. Apart from some grubby fingermarks, there's no obvious difference. Oh, wait, the cross hole is in a slightly different place.

I expect I'll now enjoy my first breakage shortly....