Silent Case Fan : 8 rubber pads which can make your rig more quietly (34.49 dBA) when the fans work with high performance.
pwm
GeeekPi Raspberry Pi Mini Tower NAS Kit, Raspberry Pi ICE Tower Cooler with PWM RGB Fan, M.2 SATA SSD Expansion Board, GPIO 1 to 2 Expansion Board for Raspberry Pi 4 Model B
This kit contains an M.2 SATA SSD expansion board which can expand the mass storage for your Raspberry Pi. The case is made of ABS material,This kit turns your Raspberry Pi into a mobile mini-host.