Constix® Validation Swabs For surface cleaning protocols in the pharmaceutical industries. The polynit fabric that makes up the head of the swab undergoes a proprietary process to reduce background Total Organic Carbon levels. The SV-1 swab consists of a large, flat head (0.4'' x 1.0'') with a flexible handle and this SV-2 has a smaller swab head (0.25'' x 0.8'').