modifying hc-sr04

Other Hardware General Electronics
10

so far im looking at these 2 sets of transducers,

https://www.ebay.com/itm/2PCS-18MM-40KHZ-Waterproof-Ultrasonic-Sensor-Receiver-Transmitter-1R-1T/111151241872?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D50998%26meid%3Da2237f710ccf48ab98bff54aff256159%26pid%3D100005%26rk%3D2%26rkt%3D12%26sd%3D300977001763%26itm%3D111151241872&_trksid=p2047675.c100005.m1851

or part number "US1440" from this website? https://www.futurlec.com/Ultrasonic_Sensors.shtml