Our architectural element construction customer ordered approximately 4,000 pcs of these custom large stainless steel spacers. 5/16-18 thread was incorporated internally, 1-1/4 inches of thread min on each side. The gap between the two sides of thread was drilled all the way through for improved production time, allowing the entire part to be drilled through and then each side tapped on both sides. The outside diameter was set at 1/2" and the overall length at 3". Tolerances on all dimensions were +/- .015". 303 stainless steel material was used for production and material certs are available upon request.