CVS is adding surge protection to all of the Differential input amplifiers as new PC boards are ordered.  The new rating on theses inputs will be 8kv contact and 15kv air. 

As of 10/06 the following products will have this new feature:

DA-3160,  DA-3080,  DA-3212, 
DA-43,  DA-112,  DA-2400,  DA-3600, 
DA-4800,  DA-26,
DA-2120,  DA-3400,  DA-4060, 
DA-4120,  DA-8060,  CDA-43, 
CDA-3080,  CDA-3160