This class of boat is often referred to as the Thresher and Permit class because it started with the first boat 'Thresher' (SSN-593). Thresher was refinement to the 'Skipjack' class, retaining the bulbous nose but with an elongated hull and was built with emphasis being placed on more quietness for stealth.
The Thresher was lost on On 9 April 1963 about 200 miles from Cape Cod due to what is believed to be issues in her construction and design. After an extensive investigation, numerous modifications and improvements were done to the designed and the class was renamed after the next hull (SSN-594) was launched under the name 'Permit'.
Micor-Mir's kit has fine engraved details on the dorsal and ventral sides of the hull and to preserve this detail the hull parts are split horizontaly as opposed to the more common vertical hull split.
A photo etch prop and cleats are included. Here is the parts layout:
