BEST BUY TomCat IUI Catheter with syringe. The TomCat IUI catheter is designed with a flexible body which enables the catheter to fit itself to the curvature of the uterus. It is relatively a small and maneuverable IUI catheter, 4.5" length, 3.5fr. and open end. The TomCat IUI catheters are sterile, individually packaged. 10/PK. Priced per Pack.