We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember robgraham
saying something like:

Dave - I read this thread as indicating that these bolts are only
suitable for concrete. Is that the case or do they function just as
well in brick or stone ?

If you read the Rawlplug page...
"SUITABLE FOR USE IN:
Pre-drilled o 6mm:
concrete,
full and hollow brick,
clinker brick,
stone,
structural clay tile.
Without pre-drilling:
aerated concrete,
timber. "