Particle traps and meters fitted with particle traps are described for removing particles from a gas flowing through a gas meter, for example, removing particles from a gas flowing through an ultrasonic gas meter serving a domestic property. In one example, the particle trap has a body which defines a space defined by first and second portions of the body and housing a filter, an inlet through which gas can enter the space, and an outlet through which the gas can exit the space. The inlet and outlet are defined in the first portion and second portion is spaced away from the outlet.