I have found the C33H-6-4R Starrett Combi Square to be a marvel of machining. The 90 & 45 degree angles checked out accurately. The finnish on the head was flawless. The slide mechanism was silk smooth - no jamming or rough spots. The satin chrome finnish on the blade eliminates glare and makes the blackened numbers and lines  easy to  read under all lighting conditions. The built in level was accurate and although I don't use the scribe for my work it fits snuggly in its holder. No fear of losing it. I highly recommend this premium square.