This product is either discontinued or we cannot get that from suppliers.
Cisco WS-X4748-SFP-E Catalyst 4500 E-series 48-port, Per-Slot Bandwidth 48 Gbps, Rated MTBF (Hours) 876,100, L2-4 Jumbo Frame support Up to 9216 bytes.
Cisco Catalyst WS-X4748-SFP-E line-card is designed for requiring line-rate capability for enterprise, mid-market and commercial core and distribution deployments.