Standard parts, the terminals 250 and 187 are general-purpose models, can also be said to be 6.3 or 4.8 type type! Plug spring terminal specification is based on the width of the male plug defined, such as: 250 refers to the conversion to metric is 0.25 0.25 * 6.35 = 25.4, and 187 refers to the conversion to metric is 0.187 inches 0.187 * 25.4 = 4.75≈4.8