A SIB-Tower 12 Production (Tom and Jerry & Chuck Jones)

I was catching some Tom & Jerry on Cartoon Network today. They were airing a string of those directed and/or produced by Chuck Jones. When “Snowbody Loves Me” comes on I noticed something unusual in the credits – a logo acclaiming that this is a ‘SIB Tower-12 production’. I note that several others T&Js done by Jones’ unit (not all mind you) are also a ‘SIB Tower-12 production’.

Now, all of you American animation buffs out there, who or what is ‘SIB Tower-12’ and what do they do?