S3900-24T4S-R is an advanced Layer 2 Plus (Layer 3 Lite) Gigabit managed stackable switches with 24x 10/100/1000BASE-T and 4x 10Gb SFP+ uplinks, dual redundant power supplies and the fanless design guarantees the switch always working silently, and ensures that the power supply of the switch will not be interrupted even if it fails, providing improved ease of use, highly secure business operations, improved sustainability, and a borderless network experience. The S3900 series switches support stacking capability with 1 and 10 Gigabit connectivity and advanced QoS to the network edge, while maintaining simple management. The S3900 series are ideal Gigabit access and aggregation switches designed for SMB, enterprise, midmarket, and branch office networks to provide lower total cost of ownership.