This International Standard specifies technical characteristics and strength requirements for fork-arm extensions and telescopic fork arms for fork-lift trucks. It applies to fork-arm extensions and telescopic fork arms designed for use on stacking lift trucks, as defined in ISO 5053, having fork-arm carriers and, in the case of fork-arm extensions, hook-on fork arms conforming to ISO 2330. This International Standard does not apply to integral transverse telescopic fork devices or scissor-action reach devices.