Sheathed 69 x 0.75mm multi-core (OD of sheathing: 12mm).
Star ceiling 'Infinity mix' sheathed multi-core fibre. (OD of sheathing: 11mm)
This is what we use when manufacturing our Infinity home cinema panels and it's available for DIY home cinema enthusiasts too. The 4 different fibre diameters give an enhanced 3D look to the stars.
80 x 0.50mm
14 x 0.75mm
5 x 1.00mm
1 x 1.50mm
Sheathed 10 strand (8 x 0.75mm and 2 x 1.00mm) OD of sheathing: 4.50mm.