diff --git a/Specification.md b/Specification.md
index ba2cd3c..1173d51 100644
--- a/Specification.md
+++ b/Specification.md
@@ -64,4 +64,42 @@ Position | Meaning
 32 | Return Receipt Requested: `1` if true, otherwise empty
 33 | Special rate eligibility: `M` for Media Mail, `L` for Library Mail, empty if not claiming eligibility
 34 | Insurance amount, USD
-35 | Signature services. 1: Signature required, 2: Adult signature required, 3: Restricted delivery signature, 4: Adult restricted signature, 5: Indirect signature.
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+35 | Signature services. 1: Signature required, 2: Adult signature required, 3: Restricted delivery signature, 4: Adult restricted signature, 5: Indirect signature.
+
+## Appendix
+
+### Item Types
+
+The following values are allowed for field 24 in a `full` type code:
+
+* (empty) when a custom size and weight item is being shipped
+* Card
+* Letter
+* Flat
+* Parcel
+* SoftPack (requires length and width set)
+* FlatRateEnvelope
+* FlatRateLegalEnvelope
+* FlatRatePaddedEnvelope
+* SmallFlatRateBox
+* MediumFlatRateBox
+* LargeFlatRateBox
+* LargeFlatRateBoxAPOFPO
+* UPSLetter
+* UPSExpressBox
+* UPS25kgBox
+* Tube (Note: UPS only)
+* Pak (Note: UPS only)
+* SmallExpressBox
+* MediumExpressBox
+* LargeExpressBox
+* FedExEnvelope
+* FedExBox
+* FedExPak
+* FedExTube
+* FedEx10kgBox
+* FedEx25kgBox
+* FedExSmallBox
+* FedExMediumBox
+* FedExLargeBox
+* FedExExtraLargeBox
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