All items contain a 1-byte prefix which denotes the basic type of the item. The HID class defines two basic formats for items:

所有项都包含一个1字节的前缀，用于标识该项的基本类型。HID 类为项定义两种基本格式：

• Short items: 1–5 bytes total length; used for the most commonly occurring items. A short item typically contains 1 or 0 bytes of optional data.

  短项：总长度为 1 至 5 字节；用于最常出现的项。短项通常包含 1 或 0 字节的可选数据。

• Long items: 3–258 bytes in length; used for items that require larger data structures for parts.

  长项：长度为 3 至 258 字节；用于其部分信息需要更大数据结构的项。

Note: This specification defines only items that use the short format. The two item formats should not be confused with types of items such as Main,Global, and Local.

注意：本规范仅定义了使用短格式的项。这两种项格式不应与项的类型（如主项、全局项和局部项）混淆。