exhibit 10. 21 certain identified information has been excluded from the exhibit because it is both not material and would likely cause competitive harm to the registrant if publicly disclosed. [ * * * ] indicates that information has been redacted. 9101 wall street suite 1300 austin, tx 78754 phone : 512 # # # - # # # - # # # # fax : 512 # # # - # # # - # # # # prepared by : various - 20201 date quote # customer id valid until customer2 [ * * * ] description3 taxed amount [ * * * ] terms and conditions 1. 50 % payment due ( date ) 2. 50 % payment due ( date ) / pick up customer acceptance ( sign below ) : print name : signature : date : sti approval : print name : signature : date : subtotal taxable — tax rate 0. 000 % tax due — other total 4 $ — if you have any questions about this price quote, please contact 512 # # # - # # # - # # # # thank you for your business! 1. this form of sales invoice was used to document various equipment sales that occurred between february 4, 2020 and march 10, 2020. the closing date of the last transaction was march 31, 2020. 2. the various customers are manufacturers whose processes require deposition equipment. 3. various manufacturing and process equipment were sold. 4. the aggregate purchase price of the sales was approximately $ 1. 2 million. exhibit 10. 21 certain identified information has been excluded from the exhibit because it is both not material and would likely cause competitive harm to the registrant if publicly disclosed. [ * * * ] indicates that information has been redacted. 9101 wall street suite 1300 austin, tx 78754 phone : 512 # # # - # # # - # # # # fax : 512 # # # - # # # - # # # # prepared by : various - 20201 date quote # customer id valid until 9101 wall street suite 1300 austin, tx 78754 phone : 512 # # # - # # # - # # # # fax : 512 # # # - # # # - # # # # prepared by : various - 20201 9101 wall street suite 1300 austin, tx 78754 phone : 512 # # # - # # # - # # # # fax : 512 # # # - # # # -