At verges and side abutments, slate-and-a-halves must be used in alternate courses. Made in Wales from over 60% recycled slate, this tops the range in both performance and looks with a proven track record on pitches down to 15. Cambrian Slates embody the beauty and character of natural slate. Made in Wales from over 60% recycled Welsh slate, Cambrian tops the range in both looks and performance and has a proven track record even on pitches as low as 15. Whilst light in weight, Cambrian's unique three point fixing makes it suitable for even the most exposed sites. Properties Nail size: 30mm x 2.65mm. Slate finish: smooth - through coloured. Certification BBA certified.