I’m still researching home security and door locks, and I stumbled upon the Addalock at Amazon. The Addalock fits between the door and jamb and prevents the door from opening easily. It’s made of chrome-plated carbon steel, and it’s for use with any door that is hinged and opens inwards. It’s designed to increase the security of hotel rooms, dorm rooms, rentals, or anywhere you can’t permanently modify the door. Amazon is offering the Addalock at $20 each with free shipping with Prime membership, but QVC (which Addalock’s site referred me to) has a set of two Addalocks on clearance for $22.79 and $5.97 shipping.