> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kraken.com/llms.txt
> Use this file to discover all available pages before exploring further.

# InstrumentDefinitionIncremental

> Market data schema, template 7

<div className="api-banner">
  <span className="api-protocol ws">SBE</span>
  <span className="api-detail">schema 34 · market data</span>
  <span className="api-tag">template 7</span>
</div>

Instrument additions, modifications and deletions.

**Direction:** Kraken → client

| ID | Field | Type | Encoding | Presence | Description |
| :- | :- | :- | :- | :- | :- |
| 2 | `instrumentDefinitionSeq` | `uint64` | field | required | Contiguous instrument-definition feed sequence, starting at one |
| 1 | `instruments` | group | group | required | |
| 1 |   ↳ `instrumentId` | [`InstrumentId`](/exchange/api-reference/sbe/market-data-types#instrumentid) | group field | required | |
| 2 |   ↳ `priceScale` | [`Scale`](/exchange/api-reference/sbe/market-data-types#scale) | group field | required | |
| 3 |   ↳ `qtyScale` | [`Scale`](/exchange/api-reference/sbe/market-data-types#scale) | group field | required | |
| 4 |   ↳ `tickSize` | [`Price`](/exchange/api-reference/sbe/market-data-types#price) | group field | required | Minimum valid price increment |
| 5 |   ↳ `qtyIncrement` | [`Quantity`](/exchange/api-reference/sbe/market-data-types#quantity) | group field | required | Smallest valid quantity step |
| 6 |   ↳ `maxTradeVol` | [`Quantity`](/exchange/api-reference/sbe/market-data-types#quantity) | group field | required | Largest quantity accepted for one order, or zero when no public limit is configured |
| 7 |   ↳ `contractMultiplier` | [`Decimal`](/exchange/api-reference/sbe/market-data-types#decimal) | group field | required | Amount of underlying represented by one contract, or one for non-contract instruments |
| 12 |   ↳ `instrumentUpdateAction` | [`InstrumentUpdateAction`](/exchange/api-reference/sbe/market-data-types#instrumentupdateaction) | group field | required | |
| 13 |   ↳ `productType` | [`ProductType`](/exchange/api-reference/sbe/market-data-types#producttype) | group field | required | |
| 14 |   ↳ `marketSector` | [`MarketSector`](/exchange/api-reference/sbe/market-data-types#marketsector) | group field | required | |
| 15 |   ↳ `maturityType` | [`MaturityType`](/exchange/api-reference/sbe/market-data-types#maturitytype) | group field | optional | |
| 8 |   ↳ `symbol` | [`SymbolEncoding`](/exchange/api-reference/sbe/market-data-types#symbolencoding) | group data | required | |
| 9 |   ↳ `currency` | [`CurrencyEncoding`](/exchange/api-reference/sbe/market-data-types#currencyencoding) | group data | required | Currency in which prices are expressed |
| 10 |   ↳ `underlyingSymbol` | [`SymbolEncoding`](/exchange/api-reference/sbe/market-data-types#symbolencoding) | group data | required | Client-facing symbol of the underlying asset, empty when not applicable |
| 11 |   ↳ `description` | [`DescriptionEncoding`](/exchange/api-reference/sbe/market-data-types#descriptionencoding) | group data | required | Human-readable instrument description |

Rows marked ↳ are fields of the repeating group above them. Each group is preceded by a `groupSizeEncoding` header (`blockLength`, `numInGroup`).

Every message is preceded by the standard SBE `messageHeader` (`blockLength`, `templateId`, `schemaId`, `version`). See [encodings](/exchange/api-reference/sbe/market-data-types#messageheader).