- IT Office Moves
The Complete IT Checklist for Moving to a Serviced Office
18 Jan, 2026
Shop›Switch Tranceivers (GBIC/SFP)›StarTech.com Cisco QSFP-40G-SR4-S Compatible QSFP+ Module - 40GBASE-SR4 - 40GbE Multimode Fiber MMF Optic Transceiver - 40GE Gigabit Ethernet QSFP+ - MPO 100m - 850nm - DDM Cisco Firepower, ASR9000, ASR1000
StarTech.com Cisco QSFP-40G-SR4-S Compatible QSFP+ Module - 40GBASE-SR4 - 40GbE Multimode Fiber MMF Optic Transceiver - 40GE Gigabit Ethernet QSFP+ - MPO 100m - 850nm - DDM Cisco Firepower, ASR9000, ASR1000
£31.40
£37.68 inc. VAT
Out of Stock(0)MPN: QSFP-40G-SR4-S-ST
🚚 Next-day delivery £4.95
Quantity:1
1
2
3
4
5
6
7
8
9
10+
Key Features
StarTech.com Cisco QSFP-40G-SR4-S Compatible QSFP+ Module, 40GBASE-SR4, 40GbE Multimode Fiber MMF Optic Transceiver, 40GE Gigabit Ethernet QSFP+ MPO 100m, 850nm DDM, Cisco Firepower,
Lifetime Warranty (QSFP-40G-SR4-S-ST)
QSFP+ transceiver module (equivalent to: Cisco QSFP-40G-SR4-S)
40GbE
40GBASE-SR4
MPO multi-mode
up to 100 m
850 nm
Product Overview
AI-generated summary
At £31.45 ex‑VAT, this is the kind of optics you buy when you’ve got a pretty standard 40GbE multimode link and you don’t want to pay Cisco-brand “tax”. It’s aimed at QSFP+ ports on Cisco platforms like Firepower/ASR gear, and in a lot of real networks the compatibility angle is what matters most—assuming your ports are happy with third‑party optics (and your vendor tickets/rules don’t require branded modules). If your use case is short‑reach MMF (your typical data‑centre patching scenario), it’s a solid value play: cheap enough to keep spares, straightforward to deploy, and usually “it just works” as long as the optics and fibre are correctly matched.
That said, I wouldn’t treat “compatible” as “no worries.” The usual gotchas are monitoring/alarms (DDM behavior can vary), switch/policy compatibility on certain Cisco models, and the eternal fibre reality check: multimode link distance and polarity/connectivity matter more than the module name on the box. If you’re buying for anything mission-critical where optics changes trigger support escalations, or you don’t have a good handle on your fibre plant, then the risk isn’t worth the saving—go brand or standardize on whatever your network team already trusts. But for a practical, established 40GbE MMF environment, this is absolutely the right price-to-performance type of purchase.
Specifications
Performance
SFP transceiver typeFiber optic
Maximum data transfer rate40000 Mbit/s
Interface typeQSFP+
Multi-mode fiber (MMF) supportedY
Fiber optic connectorMPO
Features
Product colourSilver
Hot-swapY
Mean time between failures (MTBF)244610583 h
Brand compatibilityCisco
Compatible productsSFP-40G-SR4-S
Certificates
Compliance certificatesCE,RoHS
Weight & dimensions
Width122 mm
Depth18.6 mm
Height8.5 mm
Weight37.5 g
Packaging content
Quantity per pack1 pc(s)
Packaging data
Package width120 mm
Package depth205 mm
Package height35 mm
Package weight60 g
Logistics data
Master (outer) case width120 mm
Master (outer) case length205 mm
Harmonized System (HS) code85369010
Master (outer) case height35 mm
Products per master (outer) case1 pc(s)
Similar Items
STARTECH
StarTech.com HPE J9151E Compatible SFP+ Module, 10GBASE-LR, 10GbE Single Mode (SMF) Fiber Optic Transceiver, 10GE Gigabit Ethernet SFP+, LC Connector, 10km, 1310nm, DDM, HPE 2930F, 8325, 3810M - Lifetime Warranty (J9151E-ST) - SFP+ transceiver module (equivalent to: HP J9151E) - 10GbE - 10GBase-LR - LC single-mode - up to 10 km - 1310 nm - for HPE Aruba 2930F 12, 2930M 40, 6200F 12, 6200M 24, 6300, 6405 48, 6405 96, 64XX, CX 8360
£145.08
£174.10 inc. VAT
STARTECH
StarTech.com HPE 455883-B21 Compatible SFP+ Module, 10GBASE-SR, 10GbE Multi Mode (MMF) Fiber Optic Transceiver, LC 300m, 850nm, DDM, HPE 6120XG, 6120G, Flex Fabric, Mini GBIC Transceiver - Lifetime Warranty (455883B21ST) - SFP+ transceiver module (equivalent to: HP 455883-B21) - 10GbE - 10GBase-SR - LC multi-mode - up to 300 m
£149.52
£179.42 inc. VAT
STARTECH
StarTech.com Cisco SFP-10G-LR-S Compatible SFP+ Module, 10GBASE-LR, 10GbE Single Mode (SMF) Fiber SMF Optic Transceiver, 10GbE SFP+ LC Connector, 10km, 1310nm, DDM, Cisco Firepower, ASR9000 - Lifetime Warranty (SFP10GLRSST) - SFP+ transceiver module (equivalent to: Cisco SFP-10G-LR-S) - 10GbE - 10GBase-LR - LC single-mode - up to 10 km - 1310 nm
£228.46
£274.15 inc. VAT
STARTECH
StarTech.com Cisco GLC-EX-SMD Compatible SFP Module, 1000BASE-EX, 1GbE Single Mode (SMF) Fiber SMF Optic Transceiver, 1GbE SFP, LC Connector, 40km, 1310nm, DDM, Firepower, ASR920, IE2000 - Lifetime Warranty (GLCEXSMDST) - SFP (mini-GBIC) transceiver module (equivalent to: Cisco GLC-EX-SMD) - 1GbE - 1000Base-EX - LC single-mode - up to 40 km - 1310 nm
£56.87
£68.24 inc. VAT