Issuer Free Writing Prospectus

Dated August 5, 2020

Filed pursuant to Rule 433 under the Securities Act of 1933, as amended 

Supplementing the preliminary prospectus dated August 4, 2020

Registration No. 333-239944


The issuer has filed a registration statement (including a prospectus) with the Securities and Exchange Commission (the “SEC”) for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering.


You may get these documents for free by visiting EDGAR on the SEC Web site at Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling Roth Capital Partners at 800-678-9147, or writing to Roth Capital Partners at 888 San Clemente, Newport Beach, CA 92660, Attn: Prospectus Department, or emailing