TSNMPMib.ValueType
TSNMPMib

property ValueType: Integer;

Unit
SNMPSend

Description
Define type of Value.

Supported values are: ASN1_INT, ASN1_OCTSTR, ASN1_NULL, ASN1_OBJID, ASN1_SEQ, ASN1_IPADDR, ASN1_COUNTER, ASN1_GAUGE, ASN1_TIMETICKS.

For queries use ASN1_NULL, becouse you don't know type in response!