This configuration value sets the actual buffer size, in bytes, used for size class 5 in the STREAMS buffer cache for the STREAMS I/O subsystem on this host. The source MIB's own DESCRIPTION for this object is only the placeholder text "T B S" (to be supplied), so this reading is inferred from the object's name, its position in the STREAMS admin table (whose table-level DESCRIPTION says it holds "configuration information for a STREAMS subsystem"), and its Integer32 syntax; administrators tune it, together with streamsAdmnNumBufs5, to match the message sizes typically passed through STREAMS on this host.