Related Party Transactions	6 Months Ended
Jun. 30, 2018
Related Party Transactions
Related Party Transactions	6. Related Party Transactions Prior to our IPO, we were party to a management services agreement with two Cactus LLC members, whereby Cactus paid an annual management fee totaling approximately $0.3 million, payable in four installments, each to be paid quarterly in advance, prorated for any partial year. In conjunction with our IPO, the management services agreement terminated pursuant to its terms. Management fee expense totaled less than $0.1 million and $0.2 million for the six months ended June 30, 2018 and 2017, respectively. There were no outstanding balances due as of June 30, 2018 or December 31, 2017 under the management services agreement. From time to time, we rent a plane under dry-lease from a company owned by a member of Cactus LLC. These transactions are under short-term rental arrangements. During the three months ended June 30, 2018 and 2017, expense recognized in connection with these rentals totaled $0.1 million for the respective periods. For the six months ended June 30, 2018 and 2017, expense recognized in connection with these rentals totaled $0.1 million and $0.2 million, respectively. As of June 30, 2018 and December 31, 2017, we owed less than $0.1 million, respectively, to the related party which are included in accounts payable in the consolidated balance sheets. We are also party to a TRA with certain direct and indirect holders of CW Units, including certain of our officers, directors and employees. These TRA Holders have the right in the future to receive 85% of the net cash savings, if any, in U.S. federal, state and local income tax and franchise tax that Cactus Inc. actually realizes or is deemed to realize. Distributions made by Cactus LLC generally require pro-rata distribution among all its members. During the second quarter of 2018, Cactus LLC made a $2.3 million distribution to Cactus Inc. to cover its quarterly estimated tax payment to the IRS. Accordingly, Cactus LLC made an aggregate $4.2 million pro-rata distribution to its other members.

6. Related Party Transactions

Prior to our IPO, we were party to a management services agreement with two Cactus LLC members, whereby Cactus paid an annual management fee totaling approximately $0.3 million, payable in four installments, each to be paid quarterly in advance, prorated for any partial year. In conjunction with our IPO, the management services agreement terminated pursuant to its terms. Management fee expense totaled less than $0.1 million and $0.2 million for the six months ended June 30, 2018 and 2017, respectively. There were no outstanding balances due as of June 30, 2018 or December 31, 2017 under the management services agreement.

From time to time, we rent a plane under dry-lease from a company owned by a member of Cactus LLC. These transactions are under short-term rental arrangements. During the three months ended June 30, 2018 and 2017, expense recognized in connection with these rentals totaled $0.1 million for the respective periods. For the six months ended June 30, 2018 and 2017, expense recognized in connection with these rentals totaled $0.1 million and $0.2 million, respectively. As of June 30, 2018 and December 31, 2017, we owed less than $0.1 million, respectively, to the related party which are included in accounts payable in the consolidated balance sheets.

We are also party to a TRA with certain direct and indirect holders of CW Units, including certain of our officers, directors and employees. These TRA Holders have the right in the future to receive 85% of the net cash savings, if any, in U.S. federal, state and local income tax and franchise tax that Cactus Inc. actually realizes or is deemed to realize.

Distributions made by Cactus LLC generally require pro-rata distribution among all its members. During the second quarter of 2018, Cactus LLC made a $2.3 million distribution to Cactus Inc. to cover its quarterly estimated tax payment to the IRS. Accordingly, Cactus LLC made an aggregate $4.2 million pro-rata distribution to its other members.