Amazon.com: 10Gtek 1.25G 1000Base-ZX SFP Transceiver, 1550nm SMF, up to 80 km, for Cisco GLC-ZX-SMD, Ubiquiti UniFi, Mikrotik, D-Link, Supermicro, Netgear, TP-Link, Broadcom, Linksys and More. : Electronics
For CISCO, GLC-ZX-SMD, 1000BASE-ZX SFP 1550nm 80km transceiver - AliExpress
Cisco 1000BASE-ZX SFP SMF 1550NM DOM Transceiver (GLC-ZX-SMD=)