None of this is useful without knowing the age/quality and ease of replacement tenant if it goes dark.

This is their web site: https://everseal.com/They describe it as a quartz-based product, but don't go into details of exactly what is in it.

Ideally something that is on web/app that'll allow me to keep track of different items come tax time. 

They can’t spend $5,000 per month on marketing, pay $1500 for a professional web presence, pay $600 monthly for SEO; or afford to pay VAs to screen responses.  

However, you need to be connected to the Internet in order to generate the codes on the erentallock web site.The way this works is that you setup an account with them and provide a master code.

If you are a landlord go dark and hope they move on to some other unsuspecting landlord.

They were a) smart and b) knew money and c) poked around on the world wide webs a bit.

In my market (South Texas) the property taxes and property insurance is having a severe impact on the smaller owners, who do not have 30 year financing along with the housing assistance components, are in a dark place and they will naturally expect the (us) property managers to work like dogs and squeeze blood out of turnips for the cash flow. 

I don't think tenants would abscond with their mobile homes under the cover of darkness without paying. 

I have a strong feeling the seller/listing agent is in the dark.