At only 50mm deep, the Klipsch Shallow Depth in-ceiling speakers are one of the most compact architectural speakers on the market, the Shallow Depth Series in-ceiling speakers feature a shallow depth (50mm) depth with a fully enclosed back box. Along with premium acoustics straight from the legendary Klipsch Reference 5000 architectural series, the SLM-5400-C brings high performance acoustics in an extra slim package – for great sound where installation space is limited.