a buckle includes a strap slidably looped around a strut proximate a front opening of a housing , a spring - biased , lever - like ratchet having front and rear sections and a front engagement tooth adapted to matingly engage with one of a plurality of rack teeth on an upper surface of the strap , and two opposite pivotal arms extending outside of the housing . pressing the arms will push down the rear section to lift the front section to disengage the engagement tooth from the rack tooth , thereby adjusting the buckle in discrete increments to tighten the strap .