Cystourethroscopy sheaths are available in various sizes, ranging from 15/17 Fr to 25 Fr. Smaller sheaths are well-suited for diagnostic cystoscopy, causing minimal trauma. Conversely, larger sheaths are employed in therapeutic procedures, facilitating increased irrigant flow and providing larger channels for instruments. Each sheath is equipped with an obturator designed to blunt the distal end, allowing smooth passage into the bladder without the need for visual assistance. It's generally advised to perform blind endoscope passage only in females.