RAM X-Grip Holder for most 10" tablets, with or without a case or sleeve.  These are very sturdy and have a wide range of adjustment; they should be able to accommodate a tablet with virtually any case.

It seems to work well with most folding kneeboards as well.

Compatible with the following tablets: 

Apple iPad Air, Air2, WITH OR WITHOUT LIGHT DUTY CASE
Apple iPad 4 (With Lightning Connector) WITH OR WITHOUT LIGHT DUTY CASE
Apple iPad 3 WITH OR WITHOUT LIGHT DUTY CASE
Apple iPad 2 WITH OR WITHOUT LIGHT DUTY CASE
Apple iPad 1 WITH OR WITHOUT LIGHT DUTY CASE
HP TouchPad WITH OR WITHOUT LIGHT DUTY CASE
Asus EEE Pad WITH OR WITHOUT LIGHT DUTY CASE
Asus Eee Pad Transformer WITH OR WITHOUT LIGHT DUTY CASE
Lenovo LePad Slate WITH OR WITHOUT LIGHT DUTY CASE
LG G-Slate WITH OR WITHOUT LIGHT DUTY CASE
LG Optimus Pad WITH OR WITHOUT LIGHT DUTY CASE
Motorola XOOM WITH OR WITHOUT LIGHT DUTY CASE
Motorola XYBOARD 10.1 WITH OR WITHOUT LIGHT DUTY CASE
Pandigital R90A200 WITH OR WITHOUT LIGHT DUTY CASE
Samsung Galaxy Tab 8.9 WITH OR WITHOUT LIGHT DUTY CASE
Samsung Galaxy Tab 10.1 WITH OR WITHOUT LIGHT DUTY CASE
Samsung Galaxy Tab 2 10.1 WITH OR WITHOUT LIGHT DUTY CASE
Samsung Galaxy Tab S 10.5 WITH OR WITHOUT LIGHT DUTY CASE
Toshiba Thrive WITH OR WITHOUT LIGHT DUTY CASE
Most 10" Screen Tablets

Cradle Dimensions:
Minimum Width = 6.25"
Maximum Width = 8.1"
Depth = 0.875"

Attaches to RAM standard 1" or 1.5" ball bases.   (If you already have a RAM suction cup or yoke mount for an iPad, Xoom, or other 10" tablet, this will attach to the round base and hardware you already have.)  The X-Grip™ III clamping cradle consists of a composite spring loaded cradle, expandable grip arms and additional bottom support keeper. Included are extra easy access grip knobs, located on the back of the cradle for quick release of your tablet. The X-Grip™ III clamping cradle expands and contracts for perfect fit of most 10" tablets with or without sleeves, as well as some smaller tablets. Please verify dimensions of your tablet for compatibility.
Material:
Powder Coated Marine Grade Aluminum, Marine Grade Stainless Steel Components & High Strength Composite

RAM mounts are made here in the US.  They are the best mounts available and carry a lifetime factory warranty.

We also have other c-clamp, suction cup, glareshield, vehicle leg mounts for both the iPad and the HP Touchpad with or without cases in place. 
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INTERNATIONAL CUSTOMERS PLEASE NOTE: 
  • DELIVERY TIMES are estimates - if not outright wild guesses -  from Ebay and the carriers only and are NOT guaranteed.  Our experience is that standard Priority Mail shipments to Canada, Australia and most of Europe generally arrive in a week or two but there are exceptions.  First Class Package service, where available, will take longer.  Some regions can take three weeks to a couple of months; see below for specific trouble spots.  PLEASE ALLOW ADEQUATE TIME FOR YOUR SHIPMENT TO ARRIVE.
  • CUSTOMS PROCESSING may cause additional delays; we have no control over this and are not responsible for the consequences.  
  • CUSTOMS, DUTY, BROKERAGE, VAT & OTHER charges may be imposed by the destination country; these costs are typically collected by the carrier at the time of delivery and are the responsibility of the purchaser.  We have no control over this either; please check with your local authorities FIRST if you have questions. 
  • WE CANNOT mark shipments as gifts or reduce stated values for customs purposes.
  • CUSTOMERS IN SOUTH AND CENTRAL AMERICA & SOME PARTS OF ASIA:  On occasion, USPS Priority Mail to these regions can take as long as two to three months due to customs processing and the mail systems in these areas, and tracking data can be spotty once the shipment leaves the US.  We have no control over this.  We HIGHLY recommend USPS Express Mail in these cases as it gets better tracking and generally takes no longer than a week or two even under the worst of circumstances.
  • SELECTING ANYTHING OTHER THAN USPS EXPRESS MAIL OR EBAY GLOBAL SHIPPING TELLS US AND EBAY THAT YOU UNDERSTAND THE ABOVE INCLUDING THE POTENTIAL FOR DELAYS AND AGREE TO WAIT.