Japanese company Guyatone has actually been making musical instruments and accessories since the 1950's. Currently, Guyatone focuses on a wide series of effects pedals, including Flip Series Tube Effects, Red Heat Series Effects, Mighty Micro Series Effects, and the widely popular Micro Effects Series.
Now discontinued, the Micro series were some of Guyatone's most popular effects. Measuring only 2.75" wide and 3.875" long and weighing no more than 9 oz, these pedals are great for crowded pedalboards and for musicians on a budget. They have since been replaced by the Mighty Micro Series, which offer several enhancements to both the sound and the pedal housing, with an eye towards professional use.
Since the original Micro series was so popular, you may have to search to find the pedal you want.