Unit.prototype.getPrefix = function (id) {
	if (typeof this.prefixnum === "number") {
		return this.prefixnum === id;
	}

	var i,
		prefixList = this.prefixnum;

	for (i = 0; i < prefixList.length; i += 1) {
		if (id === prefixList[i]) {
			return true;
		}
	}

	return false;
};