Steam Trade Offer Link-Link Parameters

I displayed the contents of the STEAM inventory (coupons and cards) on the site, and for the convenience of sharing, I decided to add Trade Offer Link for each item. For cards (AppID 753/6), this was no problem and the link looks like this:
https://steamcommunity.com/tradeoffer/new/?for_tradingcard=218640_2&partner=123456789&token=123456.

When you click on it, the exchange window opens and the desired card is automatically inserted (no need to search).

Faced with the problem of forming such a link for the Coupons category (AppID 753/3). A search on this issue did not provide any information at all. I made attempts to do it in different ways:

for_coupon=classid купона  
for_item=classid купона  

Data about coupons can be obtained in the JSON form by making a request:

http://steamcommunity.com/id/CUSTOMURL/inventory/json/753/3?l=russian  

How do I create such a link for coupons?