FIRST REGISTRATION RIGHTS AGREEMENT JOINDER

EXHIBIT 4.2

FIRST REGISTRATION RIGHTS AGREEMENT JOINDER

     UCI International, Inc. (“UCI”) and each of the other signatories hereto (the “Merger Date Guarantors”) hereby agrees to join and become a party to the Registration Rights Agreement, dated as of January 26, 2011, between Uncle Acquisition 2010 Corp, UCI Holdings Limited, UCI Acquisition Holdings (No. 1) Corp, UCI Acquisition Holdings (No. 2) Corp and Credit Suisse Securities (USA) LLC, as representative of the Initial Purchasers (as defined therein and, such agreement, the “Registration Rights Agreement”) as of the consummation of the Acquisition (as defined in the Registration Rights Agreement) as though it had entered into the Registration Rights Agreement on January 26, 2011. UCI and each Merger Date Guarantor hereby further agrees, effective upon the consummation of the Acquisition, to be bound by all of the covenants, agreements and obligations of “Acquisition Co.” or the “Company” or of a “Guarantor,” as the case may be, under the Registration Rights Agreement. For the avoidance of doubt, such covenants, agreements and obligations shall include, but not be limited to, the obligations enumerated in Sections 2, 3, 4, 5, 6, 8 and 10 of the Registration Rights Agreement.

	UCI INTERNATIONAL, INC.
	by	/s/ Xxxxx Zar
		Name:	Xxxxx Zar
		Title:	Vice President, General Counsel and Secretary

[Signature Page to the Joinder to the Registration Rights Agreement]

	UNITED COMPONENTS, INC.
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

	AIRTEX INDUSTRIES, LLC
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

	AIRTEX PRODUCTS, LP
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

	ASC HOLDCO, INC.
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

	ASC INDUSTRIES, INC.
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

	CHAMPION LABORATORIES, INC.
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

[Signature Page to the Joinder to the Registration Rights Agreement]

	UCI — AIRTEX HOLDINGS, INC.
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

	UCI PENNSYLVANIA, INC.
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

	UCI — XXXXX HOLDINGS, L.L.C.
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

	XXXXX MANUFACTURING, L.P.
	by	/s/ Xxxxx Xxxxxxx
		Name:	Xxxxx Xxxxxxx
		Title:	Vice President

[Signature Page to Registration Rights Joinder]

	CREDIT SUISSE SECURITIES (USA) LLC,      Acting on behalf of itself      and as representative      of the several Purchasers
	By:	/s/ Xxxxxxx X. Xxxxx
		Name:	Xxxxxxx X. Xxxxx
		Title:	Managing Director

[Signature Page to the Joinder to the Registration Rights Agreement]