What is the Sandstone CFP-100G-ER4-ST?
The Sandstone CFP-100G-ER4-ST is a CFP optical transceiver, listed by the manufacturer as "CFP-100G-ER4-ST - Cisco ASR Compatible 100G CFP, 100GBASE-ER4, 1310 nm, 40km SMF LC, DDM, C-Temp". It is part of Circular Telecom's surplus and refurbished telecom/IT equipment inventory.