The rubber bellow is a protection and has several applications.
It can be installed on things with axial movement (pneumatic cylinders, hydraulic cylinders and actuators and linear actuators tipically) otherwise it can protect things with angular movement or static systems (cable bushing, air bushing). It cannot be used where there is difference between the outside pressure and the inside pressure.
Choice of various materials
Possible realization of a new design model
The most used rubber compounds for producing the bellows are black or silicone NBR.
On demand, they can be produced in different materials: silicone, neoprene, dutral, viton, fkm, cr, vmq, hnbr, and others.
The bellows are usually pressed using the injection or in NBR rubber which is protected by the ozone, so it will be very resistant to oil and fats (also if it is immersed) but it will be discreetly resistant to the weather conditions. Some bellows are produced with EPDM rubber, so they are resistant to the weather conditions but they are not resistant to the prolonged contact with oil or fats.