The two configurations of Honeywell’s HumidIcon humidity sensors are the HIH-**20 which offers no filter, non-condensing, or the HIH-**21 which offers a hydrophobic filter and is condensation-resistant which allows for use in many condensing environments. Swapping those numbers out for 30 and 31 respectively will have the same function but will be surface mount packaging instead of through-hole.
Below is our line of HumidIcon sensors:
https://www.digikey.com/products/en?keywords=HUMIDICON
Part Numbers
HIH6030-021-001
HIH6030-021-001
HIH6030-021-001
HIH6131-021-001
HIH6131-021-001
HIH6131-021-001
HIH7130-000-001
HIH7130-000-001
HIH6121-021-001
HIH6121-021-001
HIH7120-021-001
HIH7120-021-001
HIH8120-021-001
HIH8120-021-001
HIH6130-000-001
HIH6130-000-001
HIH6130-000-001
HIH6130-021-001
HIH6130-021-001
HIH6130-021-001
HIH6120-021-001
HIH6120-021-001
HIH8131-021-001S
HIH6021-021-001S
HIH7131-000-001
HIH7131-000-001
HIH7131-000-001
HIH6131-000-001
HIH6131-000-001
HIH6131-000-001
HIH6020-021-001
HIH6020-021-001
HIH7130-021-001
HIH7130-021-001
HIH8130-021-001
HIH8130-021-001
HIH8130-021-001
HIH6030-000-001
HIH6030-000-001
HIH6030-000-001
HIH8130-000-001
HIH8130-000-001
HIH8130-000-001
HIH6021-021-001
HIH6021-021-001
HIH6031-021-001
HIH6031-021-001
HIH6031-021-001
HIH8121-021-001
HIH8121-021-001