SAVILLE is a classified NSA Type 1 encryption algorithm. It is used broadly, often for voice encryption, and implemented in a large number of encryption devices.
Little is known publicly about the algorithm itself due to its classified nature and inclusion in the NSA's Suite A. Some documentation related to the KYK-13 fill device and statements made by military officials suggest that SAVILLE has a 128-bit key. On the AIM microchip, it runs at 4% of the clock rate (compare DES at 76% and BATON at 129%). The Cypris chip mentions 2 modes; specifications for Windster and Indictor specify that they provide Saville I.
Some devices and protocols that implement SAVILLE:
References
SAVILLE Wikipedia(Text) CC BY-SA