I need a with following specifications for a Router Cisco 2821
These are the specification for the module
1000Base-LX/LH singlemode GBIC transceivers (operable over 1310nm or 1550nm range)
I tried to find it but I could not please help me in this regard.
The HWIC-1GE-SFP is a card that installs in the router. Then you need to equip this card with an SFP optics module,the GLC-LH-SM (1310nm, singlemode fiber) looks like the one you are looking for.
I hope this helps!