1.1 This specification covers requirements for first grade concentrated natural rubber latex (see Table 1) of the following categories: Category 1 Centrifuged Hevea natural latex preserved with ammonia only or by formaldehyde followed by ammonia. Category 2 Creamed Hevea natural latex preserved with ammonia only or by formaldehyde followed by ammonia. Category 3 Centrifuged Hevea natural latex preserved with low ammonia with other necessary preservatives. Category 4 Centrifuged, or centrifuged and creamed, guayule latex, or other natural rubber latex, containing less than 200 µg total protein per gram dry weight of latex, with ammonia or other hydroxide, with other necessary preservatives and stabilizers. Category 5 Centrifuged Hevea natural latex treated with aluminum hydroxide or by other means, preserved with ammonia only or by formaldehyde followed by ammonia containing less than 0.5 % non-rubber content. 1.2 This specification is not necessarily applicable to latices prepared or preserved by other methods, and shall not be construed as limiting the desirability or usefulness of other categories of latices. It does apply to natural latex sources other than Hevea brasiliensis but does not apply to compounded latex concentrates. 1.3 The analytical procedures applicable to the specifications are included and appear in the following order: